WASHINGTON, April 3 (RIA Novosti) – The US space agency NASA officially announced it has suspended some space-related contacts with Russia amid tensions over Ukraine, but said will continue working together on the International Space Station, where both US and Russian astronauts are currently living together.

While NASA and Roscosmos will seek to “maintain safe and continuous operation of the ISS,” the majority of its ongoing engagements with Russian government officials will be ceased, the space agency said in a statement Wednesday, which comes nearly three weeks after Russia finalized its reunification with Crimea, formerly a Ukrainian autonomous republic.

“Given Russia’s ongoing violation of Ukraine’s sovereignty and territorial integrity, NASA is suspending the majority of its ongoing engagements with the Russian Federation,” the agency said. Western powers have refused to recognize the results of the March 16 referendum in Crimea, which Russian President Vladimir Putin says was in full compliance with the UN charter and international law.

A Russian deputy premier in charge of the defense and space industry, Dmitry Rogozin, has mocked the move saying the space cooperation between Russia and NASA was limited to joint work on the ISS.

“NASA has halted cooperation with Roscosmos, except for work on the ISS. But our cooperation with NASA was only on ISS,” Rogozin wrote in his Twitter microblog Thursday.

A Russian rocket last week delivered three astronauts, including American Steve Swanson, who are scheduled to stay in orbit for six months. The new crew is to conduct an extensive scientific program aboard the station, in addition to maintaining a space blog of their daily activities and overseeing the arrival of several resupply vehicles.

The Russian Soyuz rocket and spacecraft, widely considered the most reliable manned space launch system in history, are currently the only means of reaching the station following the retirement of the US space shuttle in 2011.

The US pays Russia over $70 million for a single shuttle ride aboard the country’s Soyuz rocket launched from Baikonur, Kazakhstan, Plesetsk, northwestern Russia, and the Kuru space center, in French Guiana.

In a move to reduce its reliance on Russia to bring astronauts to space, NASA said it is “laser focused on a plan to return human spaceflight launches to American soil” in 2017, citing the reduced level of funding approved by Congress as a reason for postponing the plan.

“The choice here is between fully funding the plan to bring space launches back to America or continuing to send millions of dollars to the Russians.  It’s that simple.  The Obama Administration chooses to invest in America – and we are hopeful that Congress will do the same,” the statement reads.

NASA said last month that the current crisis in Ukraine would not affect the longstanding civil space co-operation with Russia, which goes back decades. A number of NASA employees have condemned the move saying scientific cooperation should not be altered by earthly politics.

Tensions between Russia and the West rose after the ouster of pro-Kremlin Ukrainian President Viktor Yanukovych in February, followed by the rise to power of Ukrainian nationalist politicians in the new government in Kiev, which Moscow considers illegitimate.

The subsequent reunification of Crimea with Russia, sparked by deepening concerns over ultranationalist rhetoric from the new authorities in Kiev, triggered the deepest crisis in relations between Moscow and the West since the end of Cold War.