Space agency spokesman Sergey Gorbunov said the eight, who had been carrying out maintenance work at the giant Soviet-era Baikonur cosmodrome in Kazakhstan, were being treated as dead.

"Eight people were working under the roof when it collapsed," Deputy Emergency Situations Minister Gennady Korotkin told Russian television station

Three sections of the five sections of 70-metre (200-foot) high roof gave way at about 0720 GMT, Gorbunov said.

A space agency source told the RIA-Novosti agency that the chances of anyone surviving the collapse were slim, saying the cause was probably linked to poor construction.

Korotkin said the Russian space agency had dispatched a rescue team from Moscow to help recover victims from the rubble of the cosmodrome, which was built in the 1950s and has gone into decline since with many buildings in a poor state of repair.

ORT television had earlier reported that at least 10 people were feared dead, although other media reports had said the victims could still be alive under the debris.

Russian news agencies said that a maintenance crew of at least eight people had been carrying out repairs on the building at the time of the accident.

Gorbunov told RTR television that he had ruled out the possibility that the collapse was caused by an attack on the Baikonur cosmodrome, which was constructed in the 1950s and is the world's oldest working launch site.

It served as the launch site for Sputnik, the first man-made satellite to orbit the Earth, on October 4, 1957, marking a giant technological leap for the Soviet Union against the United States.

And in 1961, Russian cosmonaut Yuri Gagarin took off from the site for his orbit around the Earth and became the first man in space.

Baikonur is now used for commercial and military satellite launches and sending manned rockets to the International Space Station. Nearly three-quarters of all Russian satellites and more than half of its military satellites are launched from Baikonur.

The cosmodrome's latest guest was South African space tourist Mark Shuttleworth, the 28-year-old Internet millionaire who set off on a 10-day journey to the ISS from Baikonur last month.

The status of the cosmodrome has been problematic since 1991 when the fall of communism meant it was located in the newly independent republic of Kazakhstan.

Russia and Kazakhstan signed a 1994 agreement recognising the Central Asian republic's territorial claim on Baikonur, but leasing the cosmodrome to Moscow for 115 million dollars (132 million euros) a year.

Last month, a top Russian general said the military will continue using the Baikonur cosmodrome as a satellite launch site until at least 2011 before switching operations to Russia.

SPACE.WIRE