Craig Reedie, chairman of the British Olympic Association (BOA), sits on both bodies and he today warned that there is no margin for error in security preparations for the Athens Games.

Reedie said: “There are no options. They simply have to get security as right as humanly possible.

“I am going to a meeting of the European Olympic Committee in Belgrade on Friday where this is bound to be top of the agenda.

“We will also expect the IOC’s co-ordination commission to be pretty seriously updated on current security issues when we go to Athens next week.

“These bombs are bound to be a concern but it does seem to domestic rather than international terrorism, it is nowhere near an Olympic facility and the only connection is that it is 100 days to go until the Games start.

“One wished it had not happened of course but thankfully no-one was badly hurt, and it will concentrate people’s minds even more on security, and they are pretty focused on that issue anyway.”

The early-morning bomb blasts all occurred within 30 minutes and caused extensive damage to a police station. They followed an anonymous call to a newspaper in the Greek capital warning of the attacks.

There was no immediate claim of responsibility, but suspicion is likely to fall on extremist left-wing groups linked to the November 17 terrorist network.

The group was severely weakened last year after its leaders were convicted for the murder of British diplomat Brigadier Stephen Saunders in Athens in June 2000, and other crimes.

Since those arrests, a court complex in Athens was damaged when two bombs exploded last September with a group calling itself Revolutionary Struggle claiming responsibility.

The threat of terrorism has already led to speculation that some athletes may stay away from the August 13 to 29 Games.

But Reedie said that people from the UK had been involved at the highest level in helping Athens officials plan against a terrorist threat.

He added: “We have very, very good security advice in this country and Britain has played a leading role on the advisory group for the Athens organising committee.

“We are aware of the huge effort the organising committee have made. We are aware of the huge efforts the Greek government have made.”

Theodoros Roussopoulos, Greece’s Minister of State, insisted today that the safety at the Games could be guaranteed.

He said in a statement: “The Greek government treats even isolated incidents with the necessary sense of seriousness and responsibility. According to the up-to-date evidence, there is no connection of this incident with Olympic preparations.

“The Greek authorities in co-operation with the relevant European, US and NATO authorities have designed a security system which guarantees the safety of the Athens Olympic Games.”

Suggestions that the Games could be cancelled have been rejected.

Lord Coe, a member of the International Amateur Athletics Federation’s executive, said: “We should not walk away from our Olympic obligations. No country should do that.”