Last week, the U.S. announced that it would deny export licenses for several high-technology items sought by Russia as punishment for its annexation of Crimea.
"These sanctions are out of place and inappropriate," Russia's deputy Prime Minister Dmitry Rogozin said of the move. "We have enough of our own problems."
Rogozin warned that such sanctions would have a "boomerang effect," and today he made good on those words, ending -- or at least threatening to end -- American involvement on the ISS.
He also noted that U.S. involvement is not necessary for continued use of the station, saying "the Russian segment can exist independently from the American one. The U.S. one cannot."
"After 2020, we would like to divert these funds [used for ISS] to more promising space projects," he told reporters.
The space programs of Russia and the United States have cooperated in launching and maintaining the $100 billion ISS project for the last 20 years. The station is shared by 15 nations, but the only way to get to it is via Russia's Soyuz spacecraft -- which will not welcome aboard American astronauts after 2020.
The U.S. has been keen on keeping the ISS operational until at least 2024, but Russia has now officially denied the United States' proposal to continue cooperation on the project past the end of this decade.
Russia also said that it will not sell its rocket engines to America for military satellite launches.