After astronauts on the International Space Station were forced to prepare for an evacuation, the US announced Monday that it was investigating a “debris-generating event in outer space.”

It came amid unconfirmed reports that Russia had conducted an anti-satellite weapon (ASAT) test, which are rare show-of-force demonstrations that have been criticized by the space community due to the risk they pose to crews in low Earth orbit.

“The United States Space Command is aware of a debris-generating event in space.” “We are actively working to characterize the debris field and will continue to ensure that all space-faring nations have the information they need to maneuver satellites if they are impacted,” the agency stated.

“We are also working with the State Department and NASA on these reports, and we will provide an update in the near future.”

NASA has not yet responded, but Roscomos, its Russian counterpart, has downplayed the incident.

“The object’s orbit, which forced the crew to move into spacecraft today in accordance with standard procedures, has moved away from the ISS orbit.” “The station is in the green zone,” the agency said in a tweet.

“Everything is fine with us, friends!” “We continue to work in accordance with the plan,” said Anton Shkaplerov, the outpost’s current commander, on Twitter.

According to Spaceflight Now, NASA astronauts Raja Chari, Tom Marshburn, Kayla Barron, and European Space Agency astronaut Matthias Maurer floated into their SpaceX Crew Dragon spacecraft for safety earlier.

Simultaneously, Russian cosmonauts Shkaplerov and Pyotr Dubrov, as well as NASA astronaut Mark Vande Hei, boarded a Soyuz spacecraft on the Russian segment, according to the outlet.

In an emergency, both spacecraft can be used as lifeboats to return crew to Earth.

According to US space industry analyst Serata, the debris could have been caused by a missile test.

“ASAT missile strike is now being suspected.” “According to Seradata SpaceTrak database orbital data, Cosmos 1408 (an old Soviet satellite) was in a 487 x 461 km orbit — a little higher than ISS but not by much,” the company tweeted.

“The ASAT strike on Cosmos 1408 would cause some debris to be fired below it, threatening the International Space Station with a crossing debris cloud.”