LONDON (AP) — Britain will have up to 13,500 troops deployed on land, at sea and in the skies to help protect next summer’s Olympics — twice as many as had been expected.

Typhoon fighter jets, helicopters, two warships and bomb disposal experts will all be on duty to guard against security threats to the 2012 Games, Defense Secretary Philip Hammond said in a statement Thursday to lawmakers.

The size of the deployment is far higher than the 6,000 troops previously expected and follows a decision last month to raise the security budget for the Olympics to more than 1 billion pounds ($1.6 billion).

Hammond’s announcement follows concerns that original plans to use 10,000 security guards and about 12,000 police officers would not be sufficient to guard against possible security threats. The troops will be in addition to the police and guards.

Britain’s government has said it expects the terror threat level to be set at “severe” during the July 27-Aug.12 Olympics, meaning an attempted attack is considered highly likely.

Troops will be on duty in several cities, including key venues in London, aboard boats along the River Thames, which winds through the capital and part of southern England, and in the coastal city of Weymouth where sailing events will take place.

Hammond indicated soldiers would take a key role in tackling possible threats from car bombs or other attempted terrorist attacks, with units offering “ordnance disposal, military working dogs and the capability to search vehicles and buildings.”

HMS Ocean, the largest ship in the Royal Navy’s fleet, will be berthed in Greenwich, in east London, to act as a helicopter landing site and a logistics center, while the HMS Bulwark warship will act as a maritime command post in Weymouth.

Typhoon fighter jets will be moved to the Royal Air Force’s Northolt base in north London, with Puma and Lynx helicopters also being made available.

Air force chiefs have also worked with police and Olympic organizers on an “appropriate and scalable air security plan,” Hammond said.

Hammond said during the 17-days of the Olympics about 7,500 troops would work directly on guarding venues.