The head of security for the 2012 Olympics in Britain says there will be no armed security personnel from other countries when the Games open next July in London.

Assistant Commissioner Chris Allison Tuesday dismissed reports in Britain's Guardian newspaper that 500 American FBI agents were going to be at the Games to protect U.S. interests.

The London Organizing Committee, which is responsible for preparing and staging the games, is attempting to resolve questions over venue security. But the committee recently conceded it had underestimated the strength of the security contingent necessary to protect the 32 venues for the Games. The committee originally estimated needing 10,000 security personnel but now believes as many as 21,000 will be needed.

The Guardian report said senior police officials warned ministers and the committee that 10,000 was too few, but that the costs involved prevented further action. Western intelligence agencies are worried that al-Qaida or one of its offshoots may try to disrupt the Olympics, with the U.S. team being a target.

A spokesman for Britain's Home Office says security planning is “on track” and the International Olympic Committee has “full confidence” in the strategy.