UK and Irish political leaders have condemned the apparent murder of aid worker Margaret Hassan by her kidnappers in Iraq.
Mrs Hassan's husband, Tahseen Ali Hassan, has appealed to his wife's captors saying: "I want to know if she is alive or dead. If she's dead I want to know where she is so I can bury her in peace."
A video showing a blindfolded woman being shot in the head has surfaced and has been checked by experts.
This debate is now closed. Read a selection of your comments below.
Margaret was a dedicated humanitarian, Iraqi citizen and converted Muslim. I will never understand how this atrocity has happened. She is a woman who sided with the Iraqi people, it seems impossible that these murderers if they are Iraqi could have possibly taken her life. My prayers are with her, her family and all of the innocent people suffering at the hands of this evil lurking in the shadows.
Vicki Robb, Peshawar, Pakistan
My heart goes out to the family of Margaret Hassan. After all the good she has done for the people of Iraq, I wonder, from which country do her killers come from?
Joan Harris, Chester, England
At 58 years, always a committed Christian, these acts are shaking my faith. Perhaps, in the great system of things, it is time for the watering down of the three big religions, for a world community church to emerge. Who knows? I can't be the only one who is weeping at the dreadful state of things and fearing that worse is to come. My love and prayers towards Margaret's soul and my deepest regrets to her dear husband.
Linda Richards, Hull, East Yorkshire
The story of Margaret Hassan's life, hitherto this point has been one of those few inspiring stories of humanity, in which a person transcends the barriers of race and role to become a triumphant beacon of light in a world mired with darkness. If that light has been extinguished it is a loss for our kind.
Philip, Ottawa, Canada
How awful, how disgusting, how vile! Who are these people that torture innocent people. To dispose of someone like Margaret Hassan - a truly good, kind and compassionate person who worked tirelessly for the Iraqi people - goes against the very fabric that makes us human. Margaret is in heaven now; God bless her husband and family who have to move on without her.
Joy Penberthy, Twickenham, England
I hope this atrocity will severely damage the support that these "freedom fighters" get. To kill a woman devoted to helping the is beyond contempt and I hope they are not trying to justify their actions in God's name.
Jim Kirk, Basildon UK
The killing of a defenceless woman is bad enough. The killing of an Iraqi woman citizen by a group of so called Iraqi insurgents is unthinkable. I am lost for words to describe how I feel towards those who committed this act to a woman who spent 30 years in helping the people of Iraq through thick and thin. It is such a cowardly act! My deepest condolences to he husband Tahseen and her family wherever they might be.
Ut, London, UK
The knee jerk reaction to this deplorable crime is to blame Islamic extremists, but that would be ignorant. These murderers have by their actions further distanced themselves from any sort of Godliness and are nothing but the lowest kind of criminal.
Glenn Harris, Birmingham, England
Iraq is a war zone and it's a major risk to live there. If you don't want to take risk leave the country.
Atiq, San Francisco, USA
It is a tragedy that Margaret Hassan, a courageous, giving, and innocent woman, paid a horrendous price for the political manoeuvrings of Bush and Blair.
Miriam , London
The people who did this have only unified all civilised people in their hatred for their barbarity. Many claim to be martyrs, Margaret Hassan has died a true Iraqi martyr.
Dr. Haider Al-Najjar, Bristol, UK
None of this would be happening if Bush and Blair had not blundered into an unnecessary war.
Lester Stenner, Weston super Mare UK
Interesting how we manage to find the bodies so quickly but can't find the martyrs whilst they live, praying for their lives!
If this does not motivate the good and true Muslims to stand up to the extremists and say "enough!"...what will it take?
Bill Stephen, Lethbridge, Canada
FromBBCArabic.com: This is a terrorist act that gives a very bad image to Islam. They'll make the world hate the religion which clearly forbids the killing of women, children or any defenceless beings.
Mahmoud Yahya, Cairo, Egypt
From BBCArabic.com: I am very sad to hear about the killing of a peaceful person who helped and provided aid to our poor Iraqi people who are suffering from the criminals, the enemies of humanity. These disgusting acts show their savagery and the barbarism of those who are supporting them. Let Mrs Hassan the martyr live forever in paradise and shame on her killers.
Abbas Mohamed, Iraq
From BBCArabic.com:This is another crime that will go down in the register of horror of the so-called resistance. God rest her soul.
Sultan Al Ankari, Saudi Arabia
From BBCArabic.com:Some countries want to see Iraq sink in chaos. I tell them that the culture of beheading is foreign to us Iraqis. It came with the supposed American freedom. Don't hastily accuse us of this crime.
Waleed Badrani, Nineveh, Iraq
Some Arab satellite channels are making a big fuss because an injured terrorist was shot dead, but their comment on the killing of an innocent woman like Margaret Hassan who came to Iraq with an olive branch is: a mistake that can happen from the "noble" resistance! Our condolences to her husband Mr Tahseen.
Hadiar Al Malky, Iraq
From BBCArabic.com: What can I say to her family? May God give you patience. And to her killers: What will you say to God on judgment day? I was shocked when I saw the American assault on Falluja but after hearing about the killing of Mrs Hassan, I gave them every right to launch such an operation. One of my relatives was kidnapped for 20 days, imagine where the American forces found him, then released him? In Falluja!
Mohamed Salim, Baghdad, Iraq
What a tragic waste of such a caring person. I spoke to a young Muslim girl and she so wanted to reassure me that most Muslims are gentle people, which of course they are. Unfortunately all religions have their fanatics.
Susan Moss, London UK
Does the world need any more proof that these cowards are barbarians? The only language they understand is what response they got in Falluja. If they are acting in the name of Allah, they are living in fool's paradise.
Deshibhai, Annandale VA
Iraq has lost a torch-bearer of faith in its future. The killing of Mrs Hassan is inexcusable and unforgivable. My heartfelt condolences to her husband Taseen and Mrs Hassan's family.
Those who committed this crime have broken not only their own religious laws, but those of all religions - there is no justification that can exonerate them. The Iraqi people deserve a better image than that which these criminals are giving them. Mrs Hassan worked on the side of the angels - God bless her and her family.
Sarah, Bedfordshire, UK
The first thing which comes to my mind is "why ?" The answer is terribly simple and shameful. If neither Bush nor Tony Blair had attacked Iraq, Margaret Hassan would be alive. They are partly responsible of this upsurge of violence in Iraq.
Estelle Nogaret, Rennes, France
This is horrible! What next, our children? I feel terrible for her family. I kept hope till the end. I thought they would acknowledge all the charity work she had done in their country and set her free. May she rest in peace, and may God give her family strength to continue.
Angelica, New Jersey-USA
The world has gone crazy when you bite the hand that feeds you. Margaret Hassan had chosen to be an Iraqi citizen, had chosen the religion of the Iraqi majority, had chosen an Iraqi husband and had dedicated her life to the Iraqi people through three wars.
Her reward was to be shot like an animal... a mere pawn in a pointless exercise where her supposed Western background meant she was a fair target to extract the impossible - impossible since she had no influence in the matter. How much more wrong could these people be? To shoot Mrs Hassan was the equivalent of shooting Mother Teresa on the streets of Calcutta. Just another death you may say, but the people of Iraq have lost a champion for their cause.
Patrick, Dublin, Ireland
Oh what a shocking news! Margaret lived her life helping others. Shame will continue to remain on those involved in the incident. God is going to bless her even in the grave. My tears are with the family.
Josephine Lee, Monrovia, Liberia
We have been praying for Margaret and her family during these last few weeks, dreading this terrible news which has been released today. Margaret has not died in vain; this is a turning point when the Iraqi nation finally recognises the cowardly acts of terrorism and work together to overcome. May God bless and strengthen all those family members and aid workers who feel so full of grief today.
Brian Oakley, Recife, Brazil
How terribly sad that a woman who spent her entire life trying to improve the life of Iraqis is targeted for such brutality. She was targeted apparently simply because she was born in the West, with no regard to her life's work.
Eileen McNamara, Ennis, Ireland
This is so vicious and senseless it defies belief. Iraqis on all sides denounced the kidnapping. The culprits never, as far as I am aware, claimed to be acting in the name of Islam or anything else. I suspect that whoever did this will be found and punished in one way or another - everybody despises him.
Paul, Doha, Qatar
Such a waste of a great life. What a wonderful woman doing good for those less fortunate than herself. This was a woman who worked tirelessly for nothing. God bless her.
Sophie, Belfast, Ireland
Sorry for her. Iraq is the most dangerous place in the world. She was not an American soldier, she was just a humanitarian worker. Why this crime against someone who wants to help your country? It's a shame.
Diarra, Bamako, Mali
Why are these barbaric people stripping their own county of others who live to make it a better place for them? My thoughts are with her husband and family.
May she rest in peace.
Susie Bennison, UK
Those who did it are the scum of the society. They do it in the name of religion, of the oppressed when in fact they have no faith in them and they have bags of gold in their bank accounts. I just cannot believe how someone can reach to this level of filth and lowliness. Those who did it do not want something good for the Arab world. They are just afraid that when peace comes to the Arab land and our people are free to express themselves, they will be exposed as they got nothing special to offer except hatred, filth, and fear from freedom.
Mohammad, Palestinian territories
My sympathy to her family and I praise for her work through the years for Iraqis. Her killing makes no sense because even the terrorist head called for her release.
I feel this act and all those before it are an indication of the filth being dealt with. I fail to see how anyone could see this murder as beneficial. Although in war lives will be lost, people in aid organisations are not an enemy of the people and as such should not be treated so. My thoughts are with Mrs Hassan's family and friends.
Phill Upson, Derby, UK
As a Muslim I can affirmatively say this injustice must not be forgotten. It is time for the Muslim community (umma) to stand against all that is wrong and uphold justice. Every Iraqi has must bestow the duty of protecting justice at all cost on oneself. This also applies to all Muslims. As it is what Allah wants us to do!
Abdulkadir, Washington DC
As a friend and former colleague... what a tragedy for Iraq. This was a woman devoted to her adopted country. She could have left at any time, instead she chose to stay and help those suffering in Iraq. Bless you Margaret, be at peace.
Tina Fong, Adelaide, Australia
What grace and dignity worn by Mrs Hassan's family. Our thoughts and prayers are with them at such time of irreparable loss.
Emma Cave, Blandford, UK
Margaret Hassan lived her life helping others. God will bless her for her kind and thoughtful acts. She has earned a place in heaven reserved for good souls. It is her family who will suffer now.
Andrea, NY, USA
The news, if correct, is shocking. This is a horrendous act unpardonable by any yardstick. I join the entire world to condemn this horrible act of terror. Margaret has devoted her entire life for a good humanitarian cause for the Iraqi nation and the Iraqi people, who, I hope, will never forgive the perpetrators of this crime. My deepest sympathies to the grief-stricken family of Margaret and I offer my prayers for them to cross over this difficult time with courage and fortitude.
MV Jose, Dubai, United Arab Emirates
I grieve for this woman's family and their terrible loss. This is an unbearable way for a person who devoted her life to the betterment of others to meet her end. I sense from this event however, that nature seeks its own unfortunate balance.
The hugely desperate death tolls and the brutally efficient military destruction committed in this conflict seem to be breeding a great store of potential hatred and anger against the coalition forces, their culture and democracy in general. I pray that years from now this will have all been for an overall positive end. That is very difficult to see now though.
Theodor Lundin, New Paltz, New York
These cowards achieve nothing except the taking of life of truly fine people but with nil effect on the real decision-makers. Then they have the gall to wear masks - just to underline how 'brave' they all are.
Dave Smith, Wellington, New Zealand
This disgusting act just shows the low point this war has reached. This is a war where hospitals are now targets of attacks, Nepali aid workers are slaughtered, relief supplies are kept for civilians, injured unarmed POWs are shot in cold blood. This war which was supposed to be so easy and gain so much has collapsed into a race war. The main different is the US does not like to have its killing on TV, the terrorists do.
My thoughts and prayers are with Margaret Hassan's family at this difficult time. I think the fact that a defenceless and such a loving woman was murdered in this way just shows the depths of evil. I hope this doesn't stop the many committed aid workers in Iraq from completing their mission: Operation Kindness.
Mike, IL, USA
I hope they find these scum and treat them accordingly. She was innocent and a friend of the Arab world. You know this is so wrong when Zarqawi says she should be released.
Nasarul Islam, London, UK
The people who did this are shades of Satan - not humans. Condemnation in this life and everlasting pain awaits them in the next life. Very sorry to hear an innocent aid worker whose whole purpose of being in Iraq was to help has probably been killed in this way.
Amin, Bradford, UK
I am quite sure the majority of Iraqis would share our tears, horror and sadness at her death. Margaret Hassan had adopted Iraq as her home and lived helping Iraqis. The people who did this live amongst them - maybe the people of Iraq should look within themselves and help bring these murderers to justice.
Alison, Sydney, Australia
These men are driving the name of Islam to the mud. They are simply blood-hungry men who have been sprawling for people to devour. I can't believe this has anything to do with the war in Iraq. This is just human's inhuman way of living.
Uche Chigbu, Uturu, Nigeria
Terrorism has sunk to new depths this year, killing women and children in cold blood. How can these people possibly believe their God approves?
Don, Leeds, UK
Absolutely shocking. Though I commend all volunteers who work for humanitarian agencies, it was clear months ago that working in Iraq was a different kettle of fish, with the kidnap of many other aid workers. This goes against all previous wars fought where aid agencies were given free passage to help the people. Sadly the people of Iraq will suffer for the actions of the insurgents who purport to hold their (the people's) interests at heart. Everyone should get out of Iraq as there is no longer any humanitarian or monetary reason for doing so. If anyone stays and is captured by insurgents, they should not plead to the government to recall ground forces.
Gilbert Goh, London, UK
The fact that Margaret Hassan is now no longer alive and has most probably been murdered by her abductors - is an appalling testament to the base nature of these people who are indeed barbarians. These creatures have deleted themselves from the human race - there will never be a place for them to rest in this life or the next. Margaret Hassan's life and the memory of her work will remain in millions of people's hearts for generations to come. Rest in peace Margaret.
Al, London, UK
This is about as low as it gets - killing an innocent aid worker who was not political, but only helped Iraq and its people. Would rational people do this to another human being?
Kim Caldwell, Pasadena, MD, USA
My reaction? Tears, sorrow and profound sympathies for her family. And anger: more blood on Tony Blair's hands.
Patricia, Henley, UK
From Allah we come and to Him we return. But, nothing justifies her murder. Nothing.
Jana, Philadelphia, PA, USA
I don't believe the people who did this are part of the mainstream Iraqi resistance or an Islamic group. Zarqawi himself had called for Ms Hassan's release. If she has been murdered then it is a great crime for which the perpetrators will one day have to answer for.
Imran Siddique, Southend-on-Sea, UK
Vile. To kill a women of peace, a women who dedicated her life to helping people - it is simple vile. These people are not human and they certainly are not Muslims.
Steph, Detroit, MI
My heart goes out to the family who has lost a love one in such a terrible way. To the killers I must say you should be ashamed of yourself killing a helpless woman for no reason. But I know my God or yours will judge you for your acts and escape will be unlikely.
Thea Daniels, Ypsilanti, Michigan, USA
If this information is correct this is terrible news for the whole world to hear about. It is unbelievable that the abductors haven't shown kindness to her as she needed. The only thing Margaret did was to help the ordinary Iraqi people. Her distressed face will never be forgotten from the minds of millions of people.
Haris, Croydon, UK
I pray that Ms Hassan's soul is at peace. May those who treated her so cruelly be brought to swift justice.
Jonathan A Cullum, Auburn, Alabama
Extremely sad and depressing, but hardly surprising following the ill-advised attack on Falluja and damage to Mosques.
Dave, Welwyn Garden City, UK
Tragic events such as this are often used by contributors to this forum to highlight their respective opinions about the conflict in Iraq. I am sure both sides will regard Ms Hassan's death as vindication for their view. For once, it would be more appropriate to see this latest death recognised first and foremost as the needless death of a committed humanitarian who worked all of her life in service of others. Two friends of mine who were aid workers were killed in Somalia in a terrorist attack last year. It was such a dreadful waste - to lose people who gave so much to make the world a better place. My thoughts and prayers are with Ms Hassan's family. She was a noble and generous women.
Dan, London, UK
I am totally shocked and saddened by this devastating news. My heart goes out to all her family, and I can find no words to describe the cowardly and desperately sick people who would murder an innocent and defenceless woman in cold blood. My only hope is that her life will not have been taken in vain, and that the Muslim world will unite in their condemnation of this despicable act.
Mary Percy, Dubai, UAE
Anyone who would make excuses for these murders is as worthless as they are. Let's hope the world regardless of religion or colour stands up and crushes them.
I don't think there are words left in my vocabulary to describe Margaret Hassan's murderers adequately. They are an affront to humanity, and an insult to the religion in the name of which they claim to be acting. If they think this will bring them a step closer to Paradise, then I shudder to think what they would have to do to go to hell. What can you do but pray for Margaret, her husband and her family.
Rosemary Hill, Geneva, Switzerland
I think this is yet another sickening episode in the Iraq war. When will Bush etc wake up to the fact that the American action in Iraq will only breed more hostage taking episodes like this?
Katie, Aberdeen, Aberdeenshire