Hammond disclosed the measures in the House of Commons, where he faced questions about the level of provisions made for London 2012 in light of suggestions that the US is perturbed by current plans.
He said: “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 was responding to his predecessor Liam Fox, who asked for reassurance that there would be “a full level of multi-layered defence and deterrence for the London Games, including ground-to-air missiles in London”.
Fox added that ground-to-air missiles had been in place at every Games since Atlanta in 1996 as part of “an internationally accepted minimum level of protection for the Olympics”.
American government officials are said to be considering sending hundreds of their own staff, including some from the FBI, to protect their athletes at London 2012, owing to concerns over security.
Metropolitan Police assistant commissioner Chris Allison, who is also nationals Olympic security chief, said he felt “great support from the Americans”. He added: “We will have some support from other colleagues up and down the country but it is the British police who will be doing it.”
It comes months after London 2012 organisers had to drastically revise the number of security staff they planned to hire to safeguard the sporting extravaganza, from an initial estimate of 10,000 to more than 20,000.