US officials and media have expressed revulsion at the beheading of an American hostage in Iraq - Nick Berg.
Al-Qaeda allegedly had a hand in the killing of Nick Berg, 26
The killers posted a video of themselves cutting off his head on an Arabic-language website used by militant Islamic groups.
Tom DeLay, House of Representatives Majority Leader:
The image of these murderers is a shocking reminder of the people we're up against.
They are not soldiers. They're monsters, they're terrorists, and we will not rest until every last one of them is in a cell or a cemetery.
Nick Berg's murderers are going to pay - them, their partners, their allies, their cells, their suppliers, and their sponsor
Todd Shnitt, WFLA talk radio host in Florida:
Just the description of the events, of the beheading, brought out fire from our listeners. We also made the video available on our show website and that really enraged the callers. It is pure revulsion, its is absolute anger. They are spitting nails, they are spitting fire, and they want revenge.
Senator John McCain, Republican:
It's terrible, it's tragic. It also shows the stark difference between America and these barbarians. We have found instances of mistreatment of prisoners, we are addressing the issue completely.
These people have no regard for humanity or other decency and that's why we've got to win in Iraq. That's why we have to get rid of these kinds of individuals, so that the Iraqi people are never cursed with them again.
Senator Carl Levin, Senator, Democrat:
The security situation (in Iraq) is very, very bad and this would be horrific evidence of that.
Rep. Tom Tancredo, Republican:
I am eagerly awaiting public apologies and condemnation from leaders in the Arab world expressing their own personal outrage at the barbaric murder of Nick Berg, an innocent civilian.
And if such an apology is not forthcoming from the Arab world, their silence should be condemned by the civilised world.
Scott McClellan, White House Press Secretary
Our thoughts and prayers are with his family.
It (the killing) shows the true nature of the enemies of freedom. They have no regard for the lives of innocent men, women and children.
John Kerry, Democrat presidential hopeful:
I'm horrified and deeply saddened by the senseless murder of Nicholas Berg.
Senator Wayne Allard, Republican:
I think it highlights the differences between the way we do business and so frequently our adversaries do business.
Senator Bill Nelson, Democrat:
I think there's a direct correlation between these pictures (of the abuse in Iraq's prisons) coming out in public and what these guys are saying they have done in this atrocity of beheading.
Senator Arlen Specter, Republican:
In a cruel and barbaric world this conduct descends to new levels and this incident will unleash as intensive a manhunt as has ever been witnessed with the United States leading the way obviously.
It will be joined by all the civilised world in bringing these malefactors, these perpetrators to justice and just because they're wearing hoods, just because their identities are disguised doesn't mean that they can't be... apprehended.
Michael DiBartolomol, Henderson High School Principal:
We're all very much shocked by this and extremely saddened. Nick I knew personally during this whole tenure here at Henderson High School.
I will tell you that you will not find a nicer young man than Nick Berg. He was an outstanding student, he was involved in many activities.
I could still see Nick walking down the hall carrying his saxophone, and needless to say I'm just very much upset about this whole event.
Philadelphia Daily News newspaper:
Some people will wonder: where is the world's outrage over this killing compared to all the chest-beating over the abuse of Iraqi prisoners?
Isn't that a double standard? Yes, it is.
New York Post newspaper:
In case the world needed a reminder of why America is waging its War on Terror, it got one yesterday. It's hard to imagine the terror that must have filled Berg in those final moments as he realised his hooded captors really were going to kill him.
Now it's time to ratchet up the response to this war. Forget Abu Ghraib (Baghdad's prison)... This war cannot be waged with half-measures.