The satellites, which transmit telecommunication and television signals and support meteorological and earth-observation work "have outlived their guarantee," spokesman Konstantin Kreidenko said.

They "could break down at any moment," he said.

A massive breakdown would force Russia to ask foreign manufacturers for help, "which would be much more costly than to produce new satellites in Russia," he predicted.

Russia would have to spend up to 400 million dollars (443 million euros) to maintain telecommunications, television and meteorological services using foreign satellites, Vladimir Umnikov, an official at the space agency, told the agency Itar-Tass.

The sum is three times Russia's annual budget earmarked for space, he said.

Another concern is national security, he added.

"By using foreign services, we would risk our country's national security, which is partly maintained by the satellites, whose construction is a state secret," he said.

In any case, Russian production of new replacement satellites could only be gradual, due to lack of funding for the space sector, Kreidenko said.