The breakdown of Progress MS-04 was caused by damage of the propulsion system due to abnormal separation of the rocket's 3rd stage, a source reported to Interfax.

          After separation of the Progress from the launcher's 3rd stage its engine kept operating for an unknown reason. As a result the spacecraft was hit by the 3rd stage, which critically damaged its propulsion system.

          The Interfax has not yet got official confirmation of this version from Roscosmos.

      Meanwhile, the state committee is considering different versions of what happened. The results of its work will be announced not before December 20.