Dmitry Rogozin, the head of Roscosmos, said the Russian space agency will use its part of the ISS to do everything it “considers necessary and useful”.
It was the latest in a spat between the two space agencies that emerged after Russian astronauts posed with flags in what appeared to be anti-Ukraine propaganda.
Nasa had criticised those pictures, arguing that the space station is intended to be politically neutral. The US space agency’s statement was very rare, and broke with a recent policy of largely attempting to avoid any political fallouts on the floating lab, despite tensions on the ground.
“Nasa strongly rebukes Russia using the International Space Station for political purposes to support its war against Ukraine, which is fundamentally inconsistent with the station’s primary function among the 15 international participating countries to advance science and develop technology for peaceful purposes,” a spokesperson had said.
In response, Mr Rogozin said that Roscosmos would “do in the Russian segment everything what we consider necessary and useful. And I advise Western partners to cancel their stupid sanctions”.
The images that began the latest dispute had been posted on Roscosmos’s official Telegram channel earlier in the week. They showed cosmonauts in the Russian segment of the space station, holding the flags of the Luhansk People’s Republic and the Donetsk People’s Republic, and celebrating Russian military successes in Ukraine.
Mr Rogozin has been one of the most outspoken high-profile Russian officials since the invasion of Ukraine has begun. He has used his official accounts to attack US policy, repeatedly call for sanctions to end, as well as fighting with individuals including Elon Musk.
But despite those public statements, co-operation on the space station has mostly continued as planned. There were fears, for instance, that Nasa astronauts might not be able to come back down to Earth on Russian spacecraft – but such arrangements have mostly continued as normal.