"Given Russia's ongoing violation of Ukraine's sovereignty and territorial integrity, until further notice, the U.S. Government has determined that all NASA contacts with Russian Government representatives are suspended, unless the activity has been specifically excepted," Michael F O'Brien, Associate Administrator for International and Interagency Relations wrote in the memo.
The suspension prohibits NASA officials from traveling to Russia. It also means that representatives from the Russian government are not welcome in NASA facilities. Bilateral meetings, email exchanges, and teleconferences are also banned, according to the memo.
"[O]nly operational International Space Station activities have been excepted," the memo notes. Currently, the only way for astronauts to travel to and from the space station is via a Russian Soyuz spacecraft. Currently aboard the ISS are six astronauts – two American, three Russian, and one Japanese.
According to the memo, NASA has not banned multilateral meetings held outside of Russia that includes Russian participants.
NASA is expected to issue a statement later on Wednesday, NBC News reported.
This memo reverses earlier NASA assurances that cooperation between the country's space agencies would not be affected by the Ukraine crisis.
"We do not expect the current Russia-Ukraine situation to have any impact on our civil space cooperation with Russia, including our partnership on the International Space Station program," said Allard Beutel, a NASA spokesman told CNN on March 5.
A few weeks earlier, NASA Administrator Charles Bolden and Republican Congressman Mo Brooks had a heated discussion on NASA's 2015 budget and the country's dependence on Russian spacecraft to send its astronauts to the International Space Station.
"Echoing sentiments made by several members of Congress at the hearing, the NASA chief added, 'I do not want to be reliant on the Russians to get my crews to the International Space Station,' " reported MSNBC.
Under a new deal, NASA has to pay $70.7 million dollars for one seat aboard Russia's Soyuz space capsules.