Russia postpones a meeting on a nuclear arms control treaty, U.S. officials say.

Russia has postponed a scheduled meeting with U.S. officials to discuss the last remaining nuclear arms treaty between the two countries, the State Department said on Monday, in the latest sign of the diplomatic breakdown between Washington and Moscow since the invasion of Ukraine.

U.S. and Russian officials had planned to meet on Tuesday in Cairo to review the implementation of the New START treaty, which since 2011 has limited the size of both countries’ strategic nuclear arsenals to 1,500 warheads each, down from tens of thousands at the peak of the Cold War. President Biden and President Vladimir V. Putin of Russia agreed in early 2021 to extend the treaty for five years.

The State Department said in a statement that Russia had informed the United States that it was postponing the meeting of the treaty’s Bilateral Consultative Commission, which was scheduled to last for several days, and that it would propose new dates. The United States is ready to reschedule at the earliest possible date, statement said.

The United States hopes to resume inspections of Russian nuclear sites to verify Moscow’s compliance with the 2010 treaty, which officials planned to address in Cairo. The inspections were suspended as the coronavirus pandemic began sweeping across the world in March 2020.

Russia said in August of this year that it would not allow them to resume, claiming that U.S. sanctions restricting the travel of Russian officials had made reciprocal inspections of the U.S. arsenal too difficult. The State Department disputes that U.S. sanctions have affected Russia’s ability to conduct such inspections.

Despite the pause in inspections, the two sides “have continued to provide data declarations and notifications in accordance with the treaty,” Ned Price, a State Department spokesman, told reporters in August. The bilateral commission last met in October 2021, according to Mr. Price.

Russia has signaled an interest in further extending New START beyond its current 2026 expiration date. But the Biden administration has put new arms control talks with Moscow on hold since Russia invaded Ukraine on Feb. 24.