Britain's defence secretary says about 2,100 military reserves have been called up to help protect the 2012 London Olympics.

Philip Hammond confirmed in a written statement published Monday that the reservists would form part of a deployment of up to 13,500 troops on land, at sea and in the skies.

Hammond says some "reservists will provide a range of specialist capabilities and expertise, while the majority will form part of the support to Olympic venue security operations."

Last December, he confirmed the size of the military force being used to secure the summer Olympics — twice as large as had originally been expected.

Typhoon fighter jets, helicopters, two warships and bomb disposal experts will also be on duty to guard against security threats.