"The noise resembled a can being crushed," Sergei Gorbunov, spokesman for the Rosaviakosmos space agency, said.

"The cosmonauts carried out checks but found no damage to the space station's exterior and no change in air pressure," Gorbunov was quoted by NTV as saying.

The ISS was launched in 1998 as a collaboration between 16 partners including the United States, Russia, the European Union, Japan and Canada.

The station is currently inhabited by two crew, American Michael Foale and Russian Alexander Kaleri, who arrived on board last month and are due to return to earth next April.

The unidentified noise appears to have come from a Russian-built section of the station not occupied by the crew, Gorbunov said.

Last month a group of dissenting NASA scientists told The Washington Post that a growing array of hardware problems was preventing checks on the quality of air, water and radiation levels aboard the ISS.

Russia has been the only country providing transport to the ISS since the United States grounded its shuttle program following the Columbia disaster of February this year.

SPACE.WIRE