Roscosmos, the Russian Federal Space Agency, in a statement described the accident as a malfunction and said it was looking into what had happened. Russian news agencies quoted authorities in eastern Siberia as saying they are searching for the third stage of the rocket, which is believed to have crashed there.
The rocket, Proton-M, was launched from the Russia-leased Baikonur launch pad Saturday morning. Proton-M has a history of mishaps, leading to the loss of three navigation satellites last year.
Roscosmos would not provide any further details about the accident, including the exact site of the crash. The Interfax news agency, however, quoted industry sources saying the crash could result in the suspension of all upcoming Proton-M launches, including the next one in June for a British satellite.
There were also concerns Saturday about the tons of toxic fuel that the rocket was carrying, which could have exploded at the crash site.
Observers say post-Soviet Russia's space program has been hampered by a brain drain and a steady erosion of engineering and quality standards.
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