WASHINGTON (AP) – Russia’s refusal to allow on-the-ground inspections to resume is endangering the New START nuclear treaty and U.S.-Russian arms control overall, the Biden administration charged on Tuesday.

The finding was delivered to Congress and summarized in a statement by the State Department. It follows months of more hopeful U.S. assessments that the two countries would be able to salvage cooperation on limiting strategic nuclear weapons despite high tensions over Russia’s war on Ukraine.

Inspections of U.S. and Russian military sites under the New START treaty were paused by both sides because of the spread of the coronavirus in March 2020. The U.S.-Russia committee overseeing implementation of the treaty last met in October 2021, but Russia then unilaterally suspended its cooperation with the treaty’s inspection provisions in August 2022 to protest U.S. support for Ukraine.

“Russia’s refusal to facilitate inspection activities prevents the United States from exercising important rights under the treaty and threatens the viability of U.S.-Russian nuclear arms control,” the State Department said Tuesday.

The administration also blamed Russia for the failure of the two countries to resume talks required under the New START treaty.

Russia’s Foreign Ministry said last August that it had told the U.S. it was temporarily suspending on-site inspections required under the treaty. It said U.S. sanctions imposed over Russia’s February 2022 invasion of Ukraine had changed conditions between the two countries and claimed that the U.S. was blocking Russians from carrying out their own inspections at U.S. sites.

The State Department on Tuesday denied that the U.S. was blocking inspections by the Russians.

It insisted the U.S.-Russia nuclear arms control efforts were essential to the security of the U.S., its allies and the world at large.

“It is all the more important during times of tension when guardrails and clarity matter most,” the State Department said.