Disclosure under New START Treaty follows Russia’s decision to suspend its participation in the nuclear agreement.
The United States has announced it has 1,419 deployed nuclear warheads in its arsenal, as it urged Russia to release its data.
The US Department of State said it was releasing the information publicly as part of its commitments under the New START Treaty, appearing to reverse an earlier decision not to share the data.
“The United States continues to view transparency among nuclear weapon states as extremely valuable for reducing the likelihood of misperception, miscalculation, and costly arms competitions,” a spokesperson said in a statement on Tuesday.
The new Strategic Arms Reduction Treaty came into force in 2011 and was extended for a further five years in 2021.
It caps the number of strategic nuclear warheads that the US and Russia can deploy, as well as the deployment of land and submarine-based missiles and the bombers to deliver them.
But in February this year, amid a sharp deterioration in relations since Moscow’s full-scale invasion of Ukraine in February 2022, Russian President Vladimir Putin said he was suspending Russia’s participation in the agreement.
The US said that Moscow had not made any disclosures in March and was “not implementing other key provisions of the treaty” but did not elaborate.
“The United States calls on the Russian Federation to comply with its legally-binding obligations by returning to full implementation of the New START Treaty and all the stabilizing transparency and verification measures contained within it,” the State Department spokesperson added.
The latest figures show that as well as the deployed nuclear warheads, the US had 662 deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs) and heavy bombers.
In total, it said as of March 1 it had 800 delivery systems both deployed and non-deployed, the maximum allowed.
Under New START, the two countries agreed to limit the deployment of nuclear warheads to 1,550 and long-range missiles and bombers to 700.
Inspections were also part of the agreement but were suspended during the COVID-19 pandemic. Discussions on resuming inspections were supposed to have taken place in November 2022, but Russia abruptly called them off, citing US support for Ukraine.
The US and Russia account for about 90 percent of the world’s nuclear warheads.
Russia has the largest stockpile of nuclear weapons in the world, with close to 6,000 warheads, according to experts.