The United States has removed its nuclear arsenal in Britain, ending its half-century deployment there and reducing its European nuclear deployment to six locations in five countries, a report said.

The withdrawal follows the removal of nuclear weapons from the Ramstein Air Base in Germany in 2005 and Greece in 2001, according to the The Federation of American Scientists (FAS) Strategic Security Blog, citing unidentified sources.

The United States now has an estimated 150 to 240 B61 nuclear bombs scattered in Europe -- at the US Air Force bases at Aviano AB in Italy and Incirlik in Turkey, and at four European bases, in Belgium, Germany, Holland and Italy, the blog said.

In November 2000, then president Bill Clinton authorized the Pentagon to deploy 110 nuclear bombs at the Royal Air Force Lakenheath air base, 113 miles (70 miles) northeast of London, the report said.

There were 480 atomic bombs in Europe at the time, it said.

President George W. Bush updated the authorization in May 2004 with an apparent order to remove the nuclear weapons from Ramstein, the blog said. The directive might have also authorized the pullout from Lakenheath, it said.

Asked by reporters Thursday if the reported withdrawal was true, US Defense Secretary Robert Gates said: "I haven't gotten that question since I've been secretary of defense, but I think I'm not supposed to talk about that."