Russian spacecraft are trailing a US satellite used to spy on other countries, according to the commander of the US Space Force.
"This is unusual and disturbing behaviour and has the potential to create a dangerous situation in space," General John Raymond, the Space Force chief of space operations, said in a statement to Business Insider.
"The United States finds these recent activities to be concerning and do not reflect the behaviour of a responsible spacefaring nation."
The two Russian satellites have come within 100 miles (160 kilometers) of the US satellite, and the US has raised concerns about the matter to Moscow through diplomatic channels, Raymond told Time magazine's W.J. Hennigan, who first reported the story on Monday.
In November, Russia launched "a satellite that subsequently released a second satellite," and the pair have been behaving similarly to a set that Russia previously labelled "inspector satellites," Raymond said.
He said "in any other domain," such a move "would be interpreted as potentially threatening behaviour."
The Russian Embassy in Washington, DC, did not respond to a request for comment.
The move comes amid political tensions between the two countries, including over election meddling by Russia and tensions related to Ukraine and Syria.
The Russian satellites' manoeuvring was spotted by Michael Thompson, a satellite and spacecraft enthusiast.
"This is all circumstantial evidence, but there are a hell of a lot of circumstances that make it look like a known Russian inspection satellite is currently inspecting a known US spy satellite," Thompson tweeted on January 30.
The Russian Defence Ministry said in December that a manoeuvre by the satellites – in which one satellite "birthed" another – was an experiment to assess the "technical condition of domestic satellites," according to the Russian news agency TASS.
This article was originally published by Business Insider.
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