WASHINGTON (AFP) - The United States has extended the New START nuclear disarmament treaty with Russia for five years starting on Wednesday (Feb 3), Secretary of State Antony Blinken said.

"President Biden pledged to keep the American people safe from nuclear threats by restoring US leadership on arms control and non-proliferation," Mr Blinken said in a statement.

"Today, the United States took the first step towards making good on that pledge when it extended the New START Treaty with the Russian Federation for five years."

Russian President Vladimir Putin signed off last Friday on legislation extending the accord.

The New START treaty is the last remaining arms reduction pact between the former Cold War rivals.

Signed in 2010, New START caps to 1,550 the number of nuclear warheads that can be deployed by Moscow and Washington, which control the world's largest nuclear arsenals.

The agreement, which was due to expire on Friday, is seen as a rare opportunity for compromise between Moscow and Washington, whose ties have dramatically deteriorated in recent years.