Russia said Monday it would return three of the six international crew members on board the International Space Station to Earth later this week despite no immediate plans to send up their replacement.
A Russian Mission Control Centre official told RIA Novosti that the two Russians and one NASA astronauts would return on board a Soyuz TMA-21 capsule early Friday.
He said their landing in the steppes of the Central Asian republic of Kazakhstan was expected at 0038 GMT.
Their return will leave the ISS with a skeleton crew of three in breach of regular practice.
Russia had earlier delayed the next manned mission to the station from September 22 to late October at the earliest after a Souyz rocket malfunction caused an unmanned Progress cargo vessel to crash back to Earth.
It was the first such accident in several decades and raised fresh doubts about the safety of Russian spacecraft that suffered a series of embarrassing setbacks this year.
Space officials last week blamed the August 24 Soyuz accident on a one-off production fault in a rocket engine.
But they did not name the date of the next manned Soyuz space launch and only requested time for more fine-tuning and checks.
Russia is now the sole nation capable of taking humans to the station after the July withdrawal of the US space shuttle.
NASA officials said the ISS may have to be left abandoned for the first time in a decade if Russia fails to launch the next crew within two months.
(c) 2011 AFP