Smoke alarms have sounded on a Russian module at the International Space Station, and some of the crew reported smelling something that resembled burnt plastic, officials say.
The September 9 incident did not appear to be serious, but it was the latest possible mishap to rattle nerves aboard the orbiting station over the past several weeks.
The Russian space agency Roskosmos said the smoke alarms sounded on the Zvezda module and occurred as the station's batteries were being recharged.
In audio heard on a broadcast from NASA's TV feed of the station, a French astronaut can be heard reporting the smell of burning plastic.
According to Roskosmos, the crew activated air filters and returned to their "night rest" once the air quality was back to normal.
The agency said a previously scheduled space walk would continue as normal later on September 9.
That space walk is due to be performed by Russian cosmonauts Oleg Novitsky and Pyotr Dubrov, to continue integrating another Russian-built module, the Nauka science lab.
The Nauka docked with the space station in July, but shortly after docking, the module's thrusters unexpectedly turned on, sending the station briefly spinning out of position.
Russian space officials have blamed the issue on a software failure.
Meanwhile, an anonymous Russian space official last month was quoted by the TASS news agency as making a somewhat lurid allegation regarding a mysterious incident on the station in 2018. In the incident, one, or several, manmade holes were found in another Russian-built module.
The anonymous space official suggested that a NASA astronaut had experienced a medical problem involving blood flow that "could have provoked an acute psychological crisis," which, in turn, might have led her to seek a way to return to Earth before the mission was over.
The suggestion prompted strong pushback from NASA officials in Washington.