Tests of security measures for the 2004 Athens Olympics reveal deep deficiencies that have U.S. officials worried about the safety of athletes and spectators, the Washington Post reported on Saturday.

Citing U.S. intelligence reports, the paper said planners were struggling with disorganised police forces, breakdowns in maritime patrols and sluggish counter-terrorism planning.

The report said security has failed a number of tests. A pregnant woman carried fake explosives through a checkpoint and an intelligence agent placed a mock device on board a ferry.

One particular concern was a delay in getting a command and control centre for the Games fully up and running, the Post said. The centre would allow police to exchange video and audio feeds in real time and have immediate access to information.

Officials said the problems were serious but that they could be corrected before the Games begin less than a year from now.

Games organisers have planned the biggest security operation in Olympics history with a $600 million security plan. More than 45,000 police, military and special forces -- three times as many as at the 2000 Sydney Olympics -- will be on duty during the Games fortnight.

Greece has also set up an Olympics security advisory group, comprising Spain, Germany, Britain, the United States, Israel, Australia and France, to exchange know-how ahead of the Games.