Russia's top diplomat said Friday he's not very optimistic about prospects for an extension of the last remaining U.S.-Russia arms control agreement because of Washington's focus on making China sign up to the pact.

Foreign Minister Sergey Lavrov warned that Russia only wants to keep the New START treaty as much as the U.S. does and will protect its security regardless of the pact's fate.

“We only need the extension as much as the Americans do,” Lavrov said during a conference call with foreign policy experts. “If they categorically refuse, we will not try to persuade them.”

The New START treaty was signed in 2010 by U.S. President Barack Obama and then Russian President Dmitry Medvedev. The pact limits each country to no more than 1,550 deployed nuclear warheads and 700 deployed missiles and bombers and envisages sweeping on-site inspections to verify compliance.

After both Moscow and Washington withdrew from the 1987 Intermediate-range Nuclear Forces Treaty last year, the New START is the only remaining nuclear arms control deal between the two countries. It's set to expire in February 2021 unless the parties agree to extend it for another five years.

Russia has offered its extension without any conditions, while the Trump administration has pushed for a new arms control agreement that would also include China. Moscow has described that idea as unfeasible, pointing at Beijing’s refusal to negotiate any deal that would reduce its much smaller nuclear arsenal.

Lavrov dismissed the U.S. suggestions that Russia help convince Beijing to join nuclear arms cuts, saying that Moscow respects the Chinese position and considers it “undiplomatic" to push it on the issue. He reaffirmed that Russia would welcome other nuclear powers, including Britain, France and China to join nuclear arms cuts, but emphasized that it should be their own decision.

The minister noted that American and Russian negotiators last month held a round of nuclear arms control talks in Vienna and are poised to continue the discussions, but added that the U.S. insistence on having China join the talks leaves little hope for their success.

“I’m not particularly optimistic about the New START in view of the course taken by U.S. negotiators,” he said.

Lavrov emphasized that Russia is ready for the treaty to expire in February, adding that “we are absolutely confident that we can guarantee our security for a long perspective, even in the absence of this treaty.”