The US Senate has approved a landmark nuclear arms control treaty with Russia.

The vote handed US President Barack Obama a major foreign policy victory in his drive to improve ties with Moscow and curb the spread of atomic weapons to other nations.

It was an endorsement of Obama's effort to improve relations with Russia and gave a lift to his drive to resume arms control in an attempt to curb the pursuit of nuclear weapons by countries like North Korea and Iran.

The treaty will reduce long-range, strategic atomic weapons deployed by each country to no more than 1,550 within seven years. Deployed missile launchers would be cut to no more than 700.

Russian President Dmitry Medvedev, who signed the treaty with Obama in April, expressed optimism about the passage ahead of the Senate vote, saying: "I believe that it will be ratified."

The treaty must still pass Russia's parliament, a move expected next spring.