Munich, Germany ? Russian President Vladimir Putin on Saturday blamed U.S. policy for inciting other countries to seek nuclear weapons to defend themselves from an “almost uncontained use of military force” – a stinging attack that underscored growing tensions between Washington and Moscow.

“Unilateral, illegitimate actions have not solved a single problem, they have become a hotbed of further conflicts,” Putin said at a security forum attracting senior officials from around the world.

“One state, the United States, has overstepped its national borders in every way.”

The Bush administration said it was “surprised and disappointed” by Putin’s remarks. “His accusations are wrong,” said Gordon Johndroe, Bush’s national security spokesman.

In what the Russian leader’s spokesman acknowledged was his harshest criticism of the United States, Putin attacked Bush’s administration for stoking a new arms race by planning to deploy a missile defense system in eastern Europe and for backing a U.N. plan that would grant virtual independence to Serbia’s breakaway province of Kosovo.

Sen. John McCain, R-Ariz., who was also attending the conference, described Putin’s remarks as “the most aggressive speech from a Russian leader since the end of the Cold War.”

The U.S. and an assertive Russia repeatedly have butted heads during the past year, with Vice President Dick Cheney accusing Moscow of using its energy resources as “tools of intimidation or blackmail.” Washington also has been angered by Russia’s reluctance to impose meaningful sanctions against Iran, which is accused of seeking to develop nuclear weapons under the cover of a civilian atomic energy program.