Moscow on Wednesday approved an official request by the U.S. to extend the New START nuclear arms control treaty with the Russian federation for five years, media reported.

The U.S. officially proposed an extension on Tuesday after the Joe Biden administration telegraphed the move last week.

“On behalf of the United States of America, the Embassy proposes that the duration of the Treaty be extended for a period of five years, until February 5, 2026,” reads a letter dated Tuesday to the Russian Ministry of Foreign Affairs from the U.S. embassy in Moscow.

The Russian government posted the U.S. embassy’s letter online as part of a package containing Russian-language paperwork.

“In the next few days, the parties will complete the necessary procedures that ensure the functioning of this important mechanism of international law on the mutual limitation of their nuclear missile arsenals,” the Kremlin wrote in an English-language readout of Tuesday’s telephone conversation between President Joe Biden and Vladimir Putin, the Russian president.

“I find that we can both operate in the mutual self-interest of our countries as a New START agreement, and make it clear to Russia that we are — we are very concerned about their behavior,” Biden said in a press conference with reporters in Washington Tuesday afternoon.

New START lets the U.S. and Russia deploy no more than 1,550 warheads across 700 intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers, while possessing no more than 800 deployed and non-deployed bombers, intercontinental ballistic missile launchers, and submarine-launched ballistic missile launchers. Bombers count as single warheads, under the treaty.

The U.S. and Russia have until Feb. 5 to finalize a New START extension, or the treaty, ratified in 2011 during the Barack Obama administration, will lapse.

The Donald Trump administration, before Trump lost his reelection bid in November, wanted to condition a New START extension on Russia’s willingness to make overtures to China to negotiate a new trilateral arms control treaty that would also constrain Beijing’s growing nuclear arsenal.

Russia declined to make overtures to the obstinate China, which had refused to join negotiations and said its arsenal is much smaller than Moscow’s or Washington’s, and countered with a one-year New START extension that the Trump administration did not accept.

Critics of the unconditional five-year extension have said the U.S. should have, and could have, agreed only to shorter-term extensions in order to persuade Moscow to remain near the negotiating table, where the U.S. could keep ideas about follow-on treaties on the front burner. Some of these people have said New START gives Russia too free a hand with smaller, shorter-range nuclear weapons, which the treaty does not constrain.

Proponents of a five-year extension have said that five years could buy the U.S. time to pursue a follow-on treaty while enjoying half a decade of relative confidence about the larger, longer-range weapons in Moscow’s arsenal.