Amid wild rumors in Russia that a NASA astronaut deliberately drilled a hole in a Russian spacecraft docked to the International Space Station, the space agencies of the two countries released a joint statement on Thursday saying that a leak last month was being investigated and that they would refrain from further comment.

The leak, which was less than one-tenth of an inch wide, was first detected on Aug. 29. It posed no immediate threat to the crew aboard the station, and Russian astronauts quickly patched it with tape.

But the stories in Russian news media and statements by Dmitry Rogozin, general director of Roscomos, seemed to suggest a need to reaffirm cooperation between Earth’s most active space-faring powers, who jointly manage the orbiting station.

Initially, officials suggested that a micrometeorite had pierced the spacecraft. But last week, Mr. Rogozin raised the possibility of sabotage.