MOSCOW — Russia is preparing to withdraw from the Open Skies Treaty, the international pact allowing observation flights over military facilities, in response to the U.S. pullout in November, a Russian Foreign Ministry statement said Friday.

Russia’s looming exit presents another pressing arms-control challenge for the incoming Biden administration, which already has the soon-to-expire New START nuclear treaty to address with Russia.

Russia’s official exit from the treaty won’t be for six months, leaving room for possible negotiations with envoys for President-elect Joe Biden, who has said he supports the treaty.

Russia’s Foreign Ministry said in a statement that the U.S. withdrawal from the nearly 20-year-old Open Skies Treaty “significantly upended the balance of interests of signatory states.” President Trump said in May that the United States was exiting the treaty because Russia had been violating it, something Moscow denied.

In May, Biden said that in announcing the intention to withdraw from Open Skies, Trump “doubled down on his shortsighted policy of going it alone and abandoning American leadership.”

“I supported the Open Skies Treaty as a senator, because I understood that the United States and our allies would benefit from being able to observe — on short notice — what Russia and other countries in Europe were doing with their military forces,” Biden’s statement said.

The treaty is meant to reduce the chances of an accidental war by allowing mutual reconnaissance flights by parties to the 34-nation agreement. Russia raised concerns that the United States could potentially still get access to overflight intelligence gathered by its allies who remain part of the treaty.

Moscow demanded guarantees that data collected from flights over Russia wouldn’t be shared with Washington. In its statement Friday, the Foreign Ministry cited “a lack of progress in removing impediments to the further functioning of the treaty under the new circumstances.”

“This news was pretty predictable,” Konstantin Kosachev, head of the foreign affairs committee in the upper house of the Russian parliament, wrote on Facebook on Friday.

“I'll point out that it was the U.S. that quit the treaty first,” he continued. “However, it could still have been saved if not only Russia had sought that (and we clearly demonstrated that we did), but if the other signatories to the deal, primarily those from NATO, also had enough will for that.”

“The blame for this very sad scenario fully and completely rests with the U.S. and its NATO allies. Period,” he added.

Russia’s withdrawal could now trigger its ally Belarus to do the same.

Also on the agenda for the president-elect is potentially extending New START.

The 2010 treaty, which expires in February, restricts the number of deployed strategic nuclear warheads and certain launch platforms. If it is not extended or replaced, the world’s two biggest nuclear powers will return to an era without substantive restraints on their arsenals for the first time in decades. (START is an acronym for Strategic Arms Reduction Treaty.)

The treaty includes a clause that allows the leaders of both nations to extend the agreement by five years without requiring ratification. Both Biden and Russian President Vladimir Putin previously said they would agree to the five-year extension, though Moscow most recently proposed a one-year deal that included a freeze on the number of nuclear warheads on each side.