Russia says it will withdraw from the International Space Station (ISS) after 2024 and build its own station instead.
The US and Russia, along with other partners, have successfully worked together on the ISS since 1998.
But relations have soured since Russia launched military operation in Ukraine, and Russia previously threatened to quit the project because of Western sanctions against it.
Nasa said it had not yet received any official notice of Russia’s intention to withdraw from the programme.
The ISS – a joint project involving five space agencies – has been in orbit around Earth since 1998 and has been used to conduct thousands of scientific experiments.
It is approved to operate until 2024, but the US wants to extend that for six more years with the agreement of all partners.
At a meeting with Russia’s President Vladimir Putin, Head of Roskosmos Yuri Borisov said the agency would fulfil its obligations to its partners, but the decision had been taken to quit the project after 2024.
“I think that by this time we will start putting together a Russian orbital station,” Mr Borisov said, adding that the new station was his agency’s top priority.
“Good,” replied Mr Putin.