WASHINGTON — Russian Deputy Prime Minister Dmitry Rogozin, who oversees the country’s space sector, said he would ban exports of Russian-made rocket engines used to launch U.S. military satellites.

Rogozin also said via twitter that Russia does not intend to continue cooperating with the United States on the international space program beyond 2020. The White House has proposed extending station operations to 2024 and has been working to bring the program’s international partners onboard.

The rocket engine in question is the RD-180, which is used to power the first stage of United Launch Alliance’s Atlas 5 rocket, one of the U.S. military’s two main satellite launchers. The engine is built by NPO Energomash of Russia and sold to ULA by RD-Amross, a joint venture between Energomash and United Technologies Corp.

“Russia is ready to continue deliveries of RD-180 engines to the US only under the guarantee that they won’t be used in the interests of the Pentagon,” Rogozin said via Twitter May 13.

Russia is ready to continue deliveries of RD-180 engines to the US only under the guarantee that they won’t (cont) http://t.co/xsr0zuGxBY

— Dmitry Rogozin (@DRogozin) May 13, 2014

Rogozin is one of 11 senior Russian officials sanctioned by the U.S. government following Russia’s incursions into Ukraine.

A U.S. federal judge recently barred U.S. purchases of the RD-180 because of concerns that they might violate the sanctions. The ban was lifted after U.S. government officials said no decision had been made to designate NPO Energomash as a Rogozin-controlled enterprise.

The judge’s temporary ban was issued in a case brought by rocket maker Space Exploration Technologies Corp. challenging U.S. Air Force plans to buy a large batch of rockets from ULA on a sole source basis.

In a statement emailed to SpaceNews, ULA spokeswoman Jessica Rye said neither ULA nor NPO Energomash are aware of any specific restrictions on the use of RD-180 engines.  “However, if recent news reports are accurate, it affirms that SpaceX’s irresponsible actions have created unnecessary distractions, threatened U.S. military satellite operations, and undermined our future relationship with the International Space Station.”

Rye expressed hope that the United States and Russia will work together to quickly resolve the matter. She also said the Air Force and ULA have contingency plans to deal with an interruption in deliveries of the RD-180.

“ULA and our Department of Defense customers have always prepared contingency plans in the event of a supply disruption. ULA has two launch vehicles that can support all of customers’ needs. We also maintain a two-year inventory of engines to enable a smooth transition to our other rocket, Delta, which has all U.S.-produced rocket engines.”

Rogozin also tweeted that he will suspend operations of U.S. GPS satellite ground stations that are based in Russia.

“Suspending GPS stations operation in the territory of the Russian Federation from June 1st won’t affect the signal quality that Russian users are getting,” Rogozin said.  “Roscosmos (RUS Fed Space Agency) stands ready for talks with the US on equal-footed cooperation and on deploying GLONASS stations in its territory.”

Glonass is Russia’s satellite-based positioning, navigation and timing system.

According to the U.S. government’s main GPS information website, GPS.gov, there are 12 command-and-control antennas and 16 monitoring sites for the GPS system throughout the world, including facilities in the United Kingdom and South Korea. The website makes no mention of GPS ground stations in Russia.

However, there are GPS signal-reception stations in Russia that are used for scientific and engineering purposes. These sites are not part of the GPS operational infrastructure.

Late last year, a proposal to place Glonass ground stations in the United States triggered a backlash among congressional Republicans, who proposed a legislative ban on any foreign satellite navigation facilities on U.S. soil. Members of the House Armed Services also asked Defense Department leaders for a report on the threat Russian ground stations posed to the U.S. military in an authorization bill passed May 8.

Glonass was initially deployed in the 1980s but suffered from neglect following the end of the Cold War. Russian authorities have made replenishing and upgrading Glonass a priority in recent years.

Russian officials have said they hope to expand the Glonass ground network into 30 countries, including the United States and Brazil as well as Spain, Indonesia and Australia. The ground stations verify the accuracy and monitor the integrity of satellite navigation signals.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.