MOSCOW, December 26. /TASS/.  The search operation area at the crash site of the Tu-154 aircraft operated by the Russian Defense Ministry has been expanded, a source in the Russian Emergencies Ministry’s Southern Regional Center informed TASS on Monday.

"The search operation continues, its area has been expanded," the source said.

At the moment, the group involved in the search operation has been reinforced to reach 3,500 people and 200 pieces of equipment. It includes the forces of the Russian Emergencies Ministry, the Russian Defense Ministry, the Federal Air Transport Agency, the Russian Health Ministry and the law enforcement agencies. "A total of 39 vessels and 32 aerial vehicles are working in the area, unmanned aircraft are involved in the operation as well," the Russian Emergencies Ministry said.

Russian Transport Minister, Maxim Sokolov, said earlier on Monday he believes it is necessary to expand the search area for aircraft debris and bodies of those who died in the Tu-154 crash. Speaking at a meeting of the emergency operations center set up after the disaster, he asked all those involved in that search and rescue operation to expand the search area.

The group of forces in the area of the Tu-154 crash site in Sochi has been reinforced, the search and rescue operation is carried out in three shifts, the press service of the Russian Defense Ministry said on Monday.

"The search operation in the Tu-154 crash site area has not stopped for a single minute during the night. A total of seven vessels of the Black Sea Fleet, including the Suvorovets anti-sabotage boat, the Admiral Grigorovich frigate with the Kamov Ka-27 search and rescue helicopter and seven divers aboard, the Kasimov submarine chaser, a hydrographic survey vessel with advanced sonar equipment to detect the plane’s debris, the Mineralnye Vody minesweeper, diving and patrol boats carrying diving experts and high power search light installations," the ministry said.

The Russian Defense Ministry’s Tu-154 plane disappeared from radar screens at 05.40 a.m. Moscow time (02.40 a.m. GMT) shortly after taking off from the Black Sea resort of Sochi on early Sunday.

There were 92 people on board the aircraft in total, including eight crew members and 84 passengers. Among the passengers was the Executive Director of the Spravedlivaya Pomoshch (Fair Aid) charity fund, Elizaveta Glinka, better known to the Russian public as Dr. Liza, as well as military servicemen and nine reporters from Russia's Channel One, Zvezda and NTV networks.

The plane was also carrying 68 members of the famous Alexandrov Ensemble, an official army choir of the Russian Armed Forces. The ensemble was on its way to celebrate the New Year with the group of Russia’s Aerospace Forces at the Hmeymim air base in Syria. The choir’s conductor Valery Khalilov was also among the passengers