MOSCOW, December 25. /TASS/. Military investigators of the Russian Investigative Committee have opened a criminal case into the crash of the Tu-154 plane of the Defense Ministry en route to Syria's Latakia, official spokesperson Svetlana Petrenko told TASS.

The criminal case has been opened into "the violation of rules of flights safety or preparation for them," she said.

Military investigators of Russia’s Investigative Committee are seizing documents and interrogating the persons who prepared the Tu-154 plane for the flight to Syria, said Petrenko.

"Exhaustive measures are being taken to establish all the circumstances of the incident. The pre-flight documents are seized and officials who were in charge of the flight as well as technical personnel who prepared the plane for the flight and refueled it are questioned," she said.