U.S. President Donald Trump on Thursday called for replacing the New Strategic Arms Reduction Treaty (New START) between the United States and Russia with a "modernized" deal.

"We should have our Nuclear Experts work on a new, improved, and modernized Treaty that can last long into the future," Trump wrote on Truth Social.

He refused to extend the treaty, which expired on Thursday, and criticized it, saying the pact is "a badly negotiated deal by the United States" and "is being grossly violated."

Following talks in Abu Dhabi, the U.S. military said that Washington and Moscow on Thursday agreed to reestablish high-level military-to-military dialogue, a move that could signal a move towards normalizing some ties between the United States and Russia.

In a statement, the U.S. military said the aim of reestablishing the mechanism was to avoid miscalculation and escalation by either side.

"Maintaining dialogue between militaries is an important factor in global stability and peace, which can only be achieved through strength, and provides a means for increased transparency and de-escalation," the statement added.

The reestablishment comes after the commander of U.S. European Command, General Alexus Grynkewich, held talks with senior Russian and Ukrainian military officials in Abu Dhabi.

UN Secretary-General Antonio Guterres warned on Wednesday that the expiration of New START marks a "grave moment" for international peace and security.

New START, signed by Russia and the United States in 2010, aims to limit the number of deployed nuclear warheads and their delivery systems. The treaty entered into force on February 5, 2011, with an initial validity period of 10 years and was later extended through February 4, 2026.

Russian President Vladimir Putin said in September 2025 that Russia would continue to observe the core limits of the treaty for one year after its expiration, provided that the United States refrains from actions that undermine the existing strategic balance.

(With input from agencies)