A police station in the Kalithea area of Athens has been hit by three bomb explosions.
Telephone warnings preceded the blast which caused damage and slightly wounded a police officer.
Athens is hosting the 2004 Olympic Games in August, for which security has been a major concern.
It is feared the huge profile of the Games could make Athens a terrorist target.
Is security going to pose a problem for the Olympics? Would you feel safe going to the Olympics? Send us your views.
This debate has finished. Thank you for your comments.
The media has done nothing but portray Greece as archaic and lax in terms of preparing for the Games. Everyone focuses on the stadium, the tram and now the bombs. No one ever speaks of how Greece is the country with the lowest per capita to ever host the Games, or of their other mammoth-sized efforts. What about the millions spent on their upscale sanitation efforts? Greece is changing its ways for the Games, which it holds so dear. They have invested so much, yet the media only cares to rail its efforts, forcing people to reconsider their plans. If we don't return to normalcy, terrorism wins (and the subjective media gets another story to cover).
Dio Kavalieratos, Pittsburgh, PA USA
Politics should be separate to Sports. The events in themselves are about the world uniting for a common interest. Let's hope for the same tradition this year.
Sarah, Chicago, US
Bit of a shambles, but as with so many Governments, pride and self-obsessed fulfillment before national and public safety and well-being, eh?
Callum, Glasgow, Scotland
Will any senior Greek ministers be attending the Games regularly and mixing with the participants and the spectators? The answer to that question would give us the best possible indication of whether the Greek government really believes what it says about its security measures.
David Hazel, Fareham, UK
Security will be a massive problem at the Olympics. Thousands of athletes, staff etc all in different places, at different times, how is is possible to watch every place. I was in Athens in 2002 when preparations were underway for the stadiums and it was chaos and that will be the operative word for the security. I also agree with Mark Harries that whilst we are watching Athens the terrorists may stike elsewhere.
Hazel, Yorkshire, UK
Lets not forget that a bomb incident took place in LA during their games. Then they had increased security. These types of incidents could, and do, happen anywhere in the world regardless. If the terrorists have the will no country can plan and be 100 percent safe.
Ron King, Hove, UK
Why is the BBC massaging terrorists ego. Such topics only serve to fuel terrorist machinations and morale, and portray the "free world" as fearful and panicky. Terrorists should not be given such a luxury. The attitude towards terrorists should be defiance steadfastness and serenity not the trembling resignation that some have shown here.
Opu, Stockholm, Sweden
To put it bluntly, I believe it may be. The departments responsible for preparing for the Olympics in Greece don't appear to be even getting a handle on getting the stadium finished, much less something less cut and dry like security contingencies
Mike, Atlanta, US
I wander why a group of people known world over has terrorist take delight in killing and destroying in the name of so call religion, well security should be taken serious and i pray we have a successful Olympics.
Aladesanmi Adedoyin, Lagos, Nigeria
It's a shame words like Olympic Spirit have been replaced nowadays by words like Olympic Terror! It's a shame a small country that tries to revive the real Olympic Games, has been "terrorized" by western media and politics. Terrorism for the Olympic Games is not the bombs but the attempt to commercialize them and make them a political tool! If the world is not ready to share the Olympic Spirit then it does not deserve Olympic Games! Greece has always welcomed people who To put it bluntly, I believe it may be. The departments responsible for preparing for the Olympics in Greece don't appear to be even getting a handle on having the stadium finished, much less something less cut and dry like security contingencies
Mike, Atlanta, US
If terrorists are reading this, remember that Greece refused to join the war that has destroyed Iraq. We have no quarrel with Islam. We are neutral.
Alp, Athens, Greece
Let's hope and pray not, but also watch the back door in other places too. Focusing too much in one area is a good distraction. We must all be more vigilant as this is the world that we now live in.
Mike Harries, UK
The Olympics have finally come back to its rightful place, namely Greece, and it unfortunate that the actions of the US, UK, Australia, etc on the Iraq issue were taken. I will be going to Greece as I purchased tickets. Nothing will stop me. Greece I feel has handled the whole Iraqi crises very well. These bombings yesterday are the usual left-winged brigade who will go anywhere to attack. Athens thankfully has never had a large scale attack, and chances are, it should be the safest place to be this August
Peter, Sydney, Australia
Maybe some terrorists want to hit USA, UK, France or Greece but none on the target of the peaceful principles of the Olympic spirit, which are more intense than in any previous Olympic games! Let this unique combination of history and culture, inspire the whole world to celebrate the Olympic values! The best thing is to stop the prediction of impeding calamities and be sure for ourselves that we are not evoking the terrorist acts
Nicholas, France, Paris
Being Greek, I will definitely be in Athens for the Olympics. As for security, I doubt terrorists care whether the Olympics are held in Athens, Tokyo or New York. If they really want to strike, they will. If anything, Athens will be safer than any other European capital, as Greece refused to take part in the war in Iraq.
Daphne, London, UK
I would have no qualms about going to the Olympics in Greece--terrorist acts can happen anywhere at any time, be it Boston, Athens, Moscow, etc. With its security preparations, Athens is still probably the safest place to be now; it is just that Athens is under more pressure than any place in the world now to make itself a perfectly safe city. In today's world, there are no perfectly safe cities.
Mirdza, Boston, USA
A group of us are going to see my brother and others swim at the Paralympic Games in September. These are games which take place for disabled athletes after the Olympics. We are all really worried that security efforts will not be as high for these games and would urge that exactly the same amount of effort are made for them. If they aren't planning as much security, we ask why not? Lets hope everything goes smoothly and that terrorists stay away.
Timo Kindred, London, England
If they can't even complete the sports facilities what chance is there that security measures will be in place and well tested in time?
JohnM, LyneMeads, UK
Thank goodness the Olympics will take place in Greece and in Athens in particular. The Americans (9/11) the Brits (IRA) the French ( Algeria), the Germans ( 1972 Munich Olympics) the Italians (Red Brigades) will tell you that a determined group of terrorists can and will cause havoc and no amount of security will stop them. When there is a will there is always a way. However in the case of Greece and Greek people there will be no will. Greece handled the aftermath of 9/11 and the Gulf war in a remarkable way. What's more Greeks understand Middle East politics far better than any of the "major" powers and will have covered every angle of the "will" side of the terrorist attacks equation.
Viv Bumble, Leeds UK
Unfortunately, terrorism doesn't have to be Muslim based. Greece have their own " IRA" , Viv, in the form of the November 17th Group. The Greeks have asked for co-operation from other countries to help protect visitors. I, too, fear an attack elsewhere whilst the focus is on Athens.
I'm sure Europe can help on security, we have some of the best intelligence, counter terrorism agencies and Police of the World. If UK, Germany, France, Italy and Spain put all their knowledge in Greece, it will be all good. All these countries organise major competitions each year and nothing happen. It's time for Europe to take its responsibilities and independence when it comes to interior security. This cake is perhaps a little too big to be eaten by Greece but not for Europe.
Given that the Olympic Games have been, since their inception, a world celebration, bringing together people from all ethnic, geographical and religious origins, it would surely be highly counter-productive, political suicide even, for organised terrorist groups to attack The Games themselves. However, with the world's attention focussed on events in and around Athens, it must surely be not beyond the bounds of possibility that a significant terrorist strike could be launched elsewhere.
Security will be a concern but not a problem. In the dangerous times we live in it doesn't make it more secure if you are in UK or US or in Greece. Terrorists do not care about borders
Theo, Uxbridge, UK
It has been suggested apparently that the Greeks should invite the USA, UK and others to assist in the security for the games. Considering the heavy handed way the Americans behave this has to be a very bad idea. The Greeks and the other nations taking part (especially the Muslim ones) would certainly not want American troops running around and using heavy weapons on anyone they are even vaguely suspicious of.
I think of all the events that will take place this summer, the Olympics pose the biggest possibility for a terrorist attack. It will also be the most difficult to prevent. Sadly, the terrorists do not care who they kill, only that they are successful in killing. The other side of this is that an attack at the Olympics would inflame the entire world against terrorism.
The Olympics is a well televised event with a massive crowd, the perfect terrorist target. A multinational force should be put in place to ensure full security.
Prashanth Parameswaran, Washington DC
I very much doubt it matters where the Olympics are held. Terrorists have proven they can be resourceful and deceptive, if they really want to blow up the Olympics they will try it no matter where it is. What is important is that everyone remains vigilant and that all nations involved take some responsibility for the security of all. The Olympics stands nowadays as a place where everyone of all nations can compete on friendly terms - it will be sad day if this is brought to an end.
Gav Hill, St Andrews UK