What is the New START nuclear arms treaty?

Russian servicemen drive Yars RS-24 intercontinental ballistic missile systems during the Victory Day parade in Moscow on May 9, 2018 Reuters

President Vladimir Putin said on Tuesday that Russia was suspending participation in the New START nuclear arms reduction treaty with the United States, after accusing the West of being directly involved in attempts to strike its strategic air bases.

"I am forced to announce today that Russia is suspending its participation in the strategic offensive arms treaty," he said.

WHAT IS THE NEW START TREATY?

Signed by then-US President Barack Obama and his Russian counterpart Dmitry Medvedev in 2010, the New START treaty caps the number of strategic nuclear warheads that the United States and Russia can deploy.

It came into force in 2011 and was extended in 2021 for five more years after US President Joe Biden took office, and allows both US and Russian inspectors to ensure that both sides are complying with the treaty.

Under the agreement, Moscow and Washington are committed to deploying no more than 1,550 strategic nuclear warheads and a maximum of 700 long-range missiles and bombers.

Each side can conduct up to 18 inspections of strategic nuclear weapons sites every year to ensure the other has not breached the treaty's limits.

However, inspections under the agreement were put on hold in March 2020 because of the COVID-19 pandemic.

Talks between Moscow and Washington on resuming inspections were due to take place last November in Egypt, but Russia postponed them and neither side has set a new date.

HAS RUSSIA THREATENED TO PULL OUT BEFORE?

Russia said earlier this month that it wanted to preserve the treaty, despite what it called a destructive US approach to arms control.

Together, Russia and the United States account for about 90% of the world's nuclear warheads, and both sides have stressed that war between nuclear powers must be avoided at all costs.

However, Russia's invasion of Ukraine has pushed the two countries closer to direct confrontation than at any time in the past 60 years.

The United States has accused Russia of violating the treaty by not allowing inspections on its territory, while Moscow has warned that the West's determination to "defeat" Russia could stop the treaty from being renewed when it expires in 2026.

WHAT HAPPENS NOW?

Russia said last year that the danger of a nuclear conflict was real and should not be underestimated, but that it should be avoided at all costs.

Both the US and Russia have checks to ensure that their nuclear missiles cannot be used accidentally, after years of tension during the Cold War led to some near misses.

However, fears of a nuclear confrontation have increased since the Ukraine invasion. Putin has reminded the world of the size and power of Moscow's arsenal and said he is ready to use all means necessary to defend Russia's "territorial integrity".