Russia's space agency has dismissed Western media reports suggesting Russian cosmonauts joining the International Space Station had chosen to wear yellow suits with a blue trim in support of Ukraine.
The durability of US-Russian collaboration in space is being tested by heightened antagonism between the two former Cold War adversaries over Russia's three-week-old invasion of its neighbour.
The arrival of the latest cosmonaut team on Friday - warmly welcomed by four Americans, two Russians and a German crewmate already aboard - came a day after the European Space Agency announced it had suspended a joint robotic rover mission to Mars with Russia due to the conflict.
But "sometimes yellow is just yellow," space agency Roscosmos's press service said on its Telegram channel.
"The flight suits of the new crew are made in the colours of the emblem of the Bauman Moscow State Technical University, which all three cosmonauts graduated from ... To see the Ukrainian flag everywhere and in everything is crazy."
Roscosmos Director-General Dmitry Rogozin was more acerbic, saying on his personal Telegram channel that Russian cosmonauts had no sympathy for Ukrainian nationalists.
In a live-streamed news conference from the ISS on Friday, veteran cosmonaut Oleg Artemyev, the mission commander, was asked about the suits.
"Every crew picks a colour that looks different. It was our turn to pick a colour," he said. "The truth is, we had accumulated a lot of yellow fabric, so we needed to use it up. That's why we had to wear yellow flight suits."
On Saturday evening, he was quoted on Roscosmos's Telegram channel as saying the suits had been made six months ago, and that the three cosmonauts had chosen the colours of their alma mater.
"Colour is just colour. It has nothing to do with Ukraine," he said. "In these days, even though we are in space, we are together with our president and people!"
Russia invaded Ukraine, which has a blue and yellow flag, on February 24 this year. The ensuing fighting has killed thousands of people, devastated parts of cities and caused millions of Ukrainians to flee their homes, according to the United Nations.
Rogozin has suggested that US sanctions imposed in response to the invasion could destroy ISS teamwork and lead to the space station falling out of orbit.
Officials at US space agency NASA have said American and Russian crew members are aware of events on Earth but that their work has not been affected by geopolitical tensions.
Launched in 1998, the research platform has been continuously occupied since November 2000 while operated by the US-Russian-led partnership including Canada, Japan and 11 European countries.
