Russia announced that its last nuclear arms treaty with the United States has expired, ending mutual obligations on the number of deployed nuclear weapons. Moscow stated on Wednesday that the 2010 agreement, known as the New START treaty, officially expired on Thursday, freeing both sides from previous restrictions. The Russian Foreign Ministry said the United States did not respond to President Vladimir Putin’s proposal to extend the limits on missiles and warheads for another 12 months.

The New START treaty, signed in 2010 by then US President Barack Obama and Russian President Dmitry Medvedev, came into force in 2011 and was extended for five years in 2021 under President Joe Biden. The agreement had set specific limits on the number of nuclear weapons each side could deploy.

UN Secretary-General António Guterres expressed concern over the treaty’s expiration and called on Moscow and Washington to begin discussions without delay on a new framework for nuclear arms control.