The United States is said to be preparing to send up to 1,000 security agents to the 2012 London Olympics. The plan, reported by Britain's Guardian newspaper, comes amid U.S. concerns about security for the Games.

The Guardian says Washington's concerns were sparked by the British police response to London's August riots and the restriction of anti-terrorism stop-and-search powers. The American security detail, including 500 FBI agents, would be put in place to help protect U.S. diplomats and athletes.

American questioning of security procedures has frustrated British officials.

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 says 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.