Britain may deploy surface-to-air missiles to protect London during the 2012 Olympics, Defence Secretary Philip Hammond said Monday, shortly after the government rejected reports of US security fears.

Hammond told lawmakers that "all necessary measures" would be taken to protect the London games following the reports that the United States was set to send 1,000 of its own agents to the sporting event.

"I can assure you that all necessary measures to ensure the security and safety of the London Olympic Games will be taken including, if the advice of the military is that it is required, appropriate ground-to-air defences," Hammond said.

He was responding to a query by his predecessor Liam Fox who said surface-to-air missiles had been deployed at Olympic games since Atlanta in 1996.

Earlier Monday The Guardian newspaper said US officials had raised "repeated concerns" about security at the London Games and were planning to deploy 1,000 of their own agents, including 500 from the FBI.

The paper added the London Organising Committee for the Games(LOCOG) had underestimated the number of security staff it would need at the 32 Games venues, with 21,000 guards now required rather than the initial figure of 10,000.

A spokesman for the Home Office, or interior ministry, insisted that security planning was "on track" and that the International Olympic Committee (IOC) had "full confidence" in the blueprint.

"Security planning is on track and funding has been protected. The Government is committed to delivering a safe and secure Games that London, the UK and the world can enjoy," the spokesman said.

In October, British officials rejected reports that the United States had offered to send its own aircraft carrier to be stationed off the British coast during the Olympics.