Inspectors continued their three day visit to Athens on Thursday, touring key venue construction sites.

And they vowed to keep up pressure on Greece to improve facilities and organisation.

On Wednesday, Denis Oswald, the IOC's top overseer, identified issues with the city's building plans, a shortfall of hotel rooms and in alleviating traffic problems.

Oswald said: "Some aspects have not been properly covered so far - for example, security in public transport."

He also warned that better security plans needed to be imposed on current, unfinished buildings.

But he offered hope that Athens can host a "magical Games" if it resolves the problems that have plagued its preparations.

His major areas of concern are the basketball arena, and the canoe and slalom course, both of which are near the airport.

Other concerns related to a shortage of hotel rooms.

And, while the IOC has been given assurances this will not be a problem, Oswald added: "Those are nice words, nice plans but I only believe what I have confirmed."

One final issue is Athens' traffic problems and a proposed suburban rail line aimed at easing the situation.

Dimitris Avramopoulos, Athens' Mayor, has launched a legal challenge to stop the route being built after raising fears that it could worsen traffic congestion in some areas.

The IOC has called upon Greek organisers to complete a full and competent security plan by the end of its inspection on Friday.