US President Barack Obama said on Tuesday he wanted to work with Russia to resolve a nuclear stand-off with Iran but denied reports he had offered to slow deployment of a missile defense shield in exchange for Moscow's help.

The New York Times reported that Obama had sent a letter to Russian President Dmitry Medvedev suggesting he would back off deploying a system in eastern Europe to intercept and destroy missiles, a move Russia sees as a military threat, if Moscow helped stop Iran from developing long-range weapons.

"What I said in the letter is what I have said publicly, which is that the missile defense that we have talked about deploying is directed toward, not Russia, but Iran," Obama said after meeting British Prime Minister Gordon Brown.