Russia, a critical partner in the operation of the International Space Station, is threatening to stop its work on the station by 2020.
According to several reports, including one from CNN.com, Russian Deputy Prime Minister Dmitry Rogozin said Tuesday that Russia plans to focus its attention on other projects after 2020.
NASA said it hasn't received any official word about Russia backing out of their partnership.
An early pullback by Russia could create problems for the U.S., which planned to continue work on the space station at least through 2024. NASA hopes to use the time on the orbiter to gather more information on what would be needed to send astronauts into deep space.
Early this year, the White House approved a four-year extension for the space station at a price tag of about $3 billion a year.
Earlier Wednesday, NASA told Computerworld the space agency is relying on Russia's previous commitment to be a space station partner for the long haul.
"Space cooperation has been a hallmark of U.S.-Russia relations, including during the height of the Cold War, and most notably, in the past 13 consecutive years of continuous human presence on board the International Space Station," the agency said in a statement. "Ongoing operations on the ISS continue on a normal basis with last night's return of three crew members and expected launch of a new crew in the next few weeks.
"We have not received any official notification from the government of Russia on any changes in our space cooperation at this point," NASA added.
This latest twist in Russia's cooperation with NASA comes after the U.S. space agency in April announced that because of Russia's aggressive actions in Ukraine, it was scaling back (work with Russia's space agency.
At the time of the announcement, NASA was working on a list of projects it might cancel or exclude Russia from participating in.
However, NASA made it clear that it would continue to work with the Russian Federation to continue the safe and continued operation of the International Space Station.
The U.S. has depended on Russia to ferry astronauts back and forth to the space station since NASA rretired its fleet of space shuttles in 2011.
However, NASA is aiming to launch astronauts from U.S. soil again by 2017.
The day after NASA severed some ties with Russia, the agency said it was not concerned that Russia would ever leave its astronauts without a lift home.
"We've had a longstanding relationship with Roscosmos for decades," Allard Beutel, NASA's news chief, told Computerworld on April 3. "It's in everyone's best interest to safely continue maintaining the space station. We won't do anything to disrupt that and we don't expect Russia will either."
Beutel, however, admitted that NASA does not have a specific plan in place if Russia at some point refuses to transport U.S. astronauts to or from the space station.
So far, Russia has upheld its commitment to transport international astronauts to the space station and back.
On Tuesday, a Russian Soyuz space capsule ferried back to Earth three astronauts -- one Russian, one Japanese and one American -- who had spent six months aboard the space station. The capsule landed safely in Kazakhstan.
Three more astronauts -- an American, a Russian and one from the European Space Agency -- are scheduled to launch onboard a Soyuz capsule on May 28.
Russia, the U.S., Europe, Japan, and Canada are the main countries cooperating to work on and manage the space station.
This article, Russia threatens to pull out of space station partnership, was originally published at Computerworld.com.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+ or subscribe to Sharon's RSS feed . Her email address is firstname.lastname@example.org.