The crew of the International Space Station evacuated its U.S. section on Tuesday because of a leak of "harmful substances" from the cooling system, Russian news agencies reported.
They quoted an official at the Russian space agency Roscosmos as saying the situation was now under control and all six crew - three Russians, two Americans and an Italian - were safe in the Russian section of the orbiting station.
Interfax news agency said there had been an ammonia leak.