The first stage engine of the Zenit-2S rocket that failed shortly after Friday's launch operated in the normal regime during and after the liftoff, the press service of the Russian space agency Roscosmos said.

"An express analysis of the telemetry data has led to a preliminary conclusion that the first stage engine and the flight control system operated in the normal regime," Roscosmos said in a statement.

The Russian space agency also said that documents provided by Energomash, the company that had designed and produced the first stage and the flight control system, showed that no errors were made during the production.

The Sea Launch consortium, led by Energia, launched the Zenit rocket from its floating platform Odyssey at an equatorial launch site in international waters in the Pacific Ocean at 10.56 a.m. Moscow time (6.55 GMT).

The rocket fell into the sea not far from the Odyssey around 50 seconds into the flight, following an emergency shutdown of its first stage motor. The launch platform was not damaged in the failed launch.

A space industry source earlier told RIA Novosti that a malfunction in the rocket's flight control system was the most likely cause of the failure.

Source: RIA Novosti