A Russian rocket carrying a US telecommunications satellite has reportedly plunged into the Pacific Ocean, moments after it was launched from a mobile sea platform.

"There was an accident during the Zenit rocket launch," a source at the Energia corporation that makes the Zenit-3SL rocket used to launch the Intelsat satellite told the AFP news agency on Friday.

"The rocket fell into the Pacific Ocean. We have formed a commission to figure out the cause."

Energia chief Vitaly Lopota said the Russian rocket's engine appeared to fail less than a minute after the evening launch.

"We had an abnormal situation - the emergency shutdown of the first stage engine," Lopota told the state RIA Novosti news agency.

"It happened 50 seconds into the flight. We are now looking into what happened."

Other sources said the rocket had veered off course from the moment of the blast-off and pointed out that heavy waves had surrounded the Odyssey launch platform for several days.

"The rockets detected an abnormal situation linked to platform instability from the very start, and then switched the engines over [to operations] aimed at steering the rocket away from the platform," a space industry source told
the Interfax news agency.

The Intelsat-27 satellite was to provide services for media, government and other customers in the Americas and Europe, according to the website of Luxembourg-based Intelsat.

The international Sea Launch consortium has used the former Pacific Ocean oil platform to perform commercial launches since 1999. There had been only two complete failures out of the 34 missions conducted prior to Friday's launch.

Source: Agencies