The United States has voiced regret over Russia's announcement that it would exit the International Space Station after 2024 and said it was taken by surprise.
Russia has said it will leave the International Space Station "after 2024", amid tensions with the West, in a move analysts warned could lead to a halt to manned flights.
The confirmation of the long-mooted move comes as ties unravel between the Kremlin and the West over Moscow's military intervention in Ukraine and several rounds of devastating sanctions against Russia, including its space sector.
"It's an unfortunate development given the critical scientific work performed at the ISS, the valuable professional collaboration our space agencies have had over the years, and especially in light of our renewed agreement on space-flight cooperation," State Department spokesman Ned Price told reporters.
Space experts said the departure from the International Space Station would seriously affect the country's space sector and deal a major blow to the programme of manned flights, a major source of Russian pride.
"Of course we will fulfil all our obligations to our partners but the decision to leave this station after 2024 has been made," Yury Borisov, the new head of Russian space agency Roscosmos, told President Vladimir Putin, according to a Kremlin account of their meeting.
"I think that by this time we will start putting together a Russian orbital station," Borisov added, calling it the domestic space programme's main "priority".
"Good," Putin replied.
The ISS is due to be retired after 2024, although US space agency NASA says it can remain operational until 2030.
The ISS was launched in 1998 at a time of hope for US-Russia cooperation following their Space Race competition during the Cold War.
Until now, space exploration has been one of the few areas where cooperation between Russia and the US and its allies had not been wrecked by tensions over Ukraine and elsewhere.
Independent space analyst Vitaly Yegorov said it was next to impossible to build a new orbiting station from scratch in a few years, especially in the current circumstances.
Blow to manned flights
Russia is heavily reliant on imports of everything from manufacturing equipment to consumer goods and the effects of Western sanctions are expected to wreak havoc on the country's economy in the long term.
"Neither in 2024, nor in 2025, nor in 2026 will there be a Russian orbital station," Mr Yegorov told AFP.
He added that creating a full-fledged space station would take at least a decade of "the most generous funding".
Mr Yegorov said Russia's departure from the ISS meant Moscow might have to put on ice its programme of manned flights "for several years" or even "indefinitely".
The move could also see Russia abandon its chief spaceport, Baikonur, which it is renting from the former Soviet republic of Kazakhstan, Mr Yegorov said.
Soyuz rockets were the only way to reach the ISS until SpaceX, run by the billionaire Elon Musk, debuted a capsule in 2020.
The Soviet space programme can boast of several key accomplishments, including sending the first man into space in 1961 and launching the first satellite four years earlier. These feats remain a major source of national pride in Russia.
But experts say Roscosmos is now a shadow of its former self and has in recent years suffered a series of setbacks, including corruption scandals and the loss of a number of satellites and other spacecraft.
Mr Borisov, a former deputy prime minister with a military background, was appointed head of Roscosmos in mid-July.
He replaces Dmitry Rogozin, a firebrand nationalist politician known for his bombastic statements and eccentric behaviour.
Mr Rogozin had previously warned that without cooperation from Moscow, the ISS could de-orbit and fall on US or European territory.
At his meeting with Mr Putin, Mr Borisov admitted that the space industry was in a "difficult situation".
He said he would seek "to raise the bar and, first of all, to provide the Russian economy with the necessary space services", which he said included navigation, communication and data transmission.