Russia's federal space agency has said that an unmanned rocket and its payload of two communications satellites failed to reach orbit, the latest in a series of failures that has dogged Moscow's space programme.
Roscosmos said a secondary booster module of the Proton-M rocket carrying Russian and Indonesian satellites switched off earlier than expected minutes after taking off from the Baikonur cosmodrome in Kazakhstan late on Monday night.
Last August, Russia lost contact with a communications satellite shortly after a Proton-M launch. In 2007, a Proton-M carrying a Japanese communications satellite crashed.
Roscosmos spokesman Alexei Kuznetsov told the Itar Tass news agency that Roscosmos might halt Proton-M launches after an investigation.
The 165ft long booster with a payload of up to 20 metric tons has been in use since 1965.