Russian state space corporation Roscosmos said Sunday it is awaiting clarification from the U.S. National Aeronautics and Space Administration (NASA) after it has reportedly rescinded an invitation to Roscosmos head Dmitry Rogozin.

The Washington Post reported on Saturday that NASA Administrator Jim Bridenstine had said in an interview that he has rescinded Rogozin's invitation to visit the United States amid mounting criticism from Capitol Hill.

"It's strange for us that colleagues from NASA communicate with us through the media, not directly," Roscosmos spokesman Vladimir Ustimenko said, adding that Roscosmos expects NASA to explain through established channels or its representatives in Russia.

NASA Press Secretary Megan Powers said on Friday that Rogozin's planned visit in February has to be postponed and a new date for the visit has not been confirmed.

Despite long-time Russia-U.S. spats, Roscosmos and NASA have maintained close cooperation, for example, the Russian Soyuz spacecrafts have regularly transported U.S. astronauts between the International Space Station and Earth.