The U.S. slammed Russia on Monday for “recklessly” launching an anti-satellite weapons test, creating thousands of pieces of debris in space. “The test has so far generated over 1,500 pieces of trackable orbital debris and hundreds of thousands of pieces of smaller orbital debris that now threaten the interests of all nations,” the State Department said in a statement. U.S. officials said they are working alongside other countries, the State Department, and NASA to ensure other space equipment remains safe. “We are actively working to characterize the debris field and will continue to ensure all space-faring nations have the information necessary to maneuver satellites if impacted,” U.S. Space Command said in a statement.

The State Department added that Russia’s exercise—which the agency characterized as a “destructive satellite test of a direct ascent and anti-satellite missile against one of its own satellites”—increases “the risk to astronauts and cosmonauts on the International Space Station, as well as to other human spaceflight activities.” The U.S. vowed to “respond” to the country’s “irresponsible act.”