The last remaining nuclear arms pact between Russia and the United States has expired, removing caps on their atomic arsenals for the first time in over 50 years

The Russian Foreign Ministry warned Wednesday that it was ready to take decisive action to stop threats against the country, following the expiration of the New START Treaty on nuclear weapons between it and the U.

The New START treaty served as a bulwark against a renewed nuclear arms race between the US and Russia, who together possess almost 90% of the world’s atomic warheads. The bilateral accord, which is the only remaining arms control agreement between the two countries,

Russia ​said on ‌Wednesday it was open ​to diplomacy on nuclear security ‍but would resolutely ​counter any new ​threats, ⁠after what it called a mistaken and regrettable decision by the United States not to ‌stick to the missile and warhead ​limits ‌of the expiring ‍New ⁠START nuclear treaty.

The last remaining nuclear treaty between the U.S. and Russia is set to expire Thursday, ending decades of arms control between the two countries with the largest nuclear arsenals.

U.S. President Donald Trump on Thursday rejected an offer from his Russian counterpart to voluntarily extend the caps on strategic nuclear weapons deployments after the treaty that held them in check for more than two decades expired.

The last nuclear treaty ‌between ​Russia and the United States is due ‌to expire within hours, raising the risk of a new arms race in which China will ​also play a key role. The web of arms control deals negotiated in the decades since the 1962 Cuban Missile Crisis,

The New START nuclear treaty between Russia and the U.S. expired without a new agreement, removing limits on their nuclear arsenals. The treaty, which capped missiles, launchers, and warheads for both countries,