Russia reportedly has deployed one of its deadliest weapons in its fight against the Islamic State (Isis) militants in Syria -- the TOS-1A Heavy Flamethrower System.

Recent photos shared on Twitter from Syria shows at least one such Russian multiple rocket launcher and thermobaric weapons mounted on a T-72 tank chassis being deployed by the Syrian soldiers.

The development has come just as the Syrian army began a large-scale military operation in the Jobar neighborhood east of Damascus and Aleppo, supported by aircraft and artillery.

According to Russian news source Rusvesna, the TOS-1A "Solntsepyok" (blazing sun or sunheat) arrived in Syria recently.

While it is not known how many of the 24-barrel rocket launchers are deployed in Syria, their presence itself should scare the Isis.

Watch a TOS-1A Heavy Flamethrower System in action [Video]

An American science and technology magazine journalist who witnessed the TOS-1A system in action at a drill near Volgograd noted that it is capable of making life a living hell for the enemy.

Jake Swearingen, a journalist with the Popular Mechanics, noted that the Russian tank-mounted rocket launcher can incinerate eight city blocks.

The TOS-1A is classified as a flamethrower. Besides the traditional incendiary rockets, it can also fire thermobaric rockets. When fired, the thermobaric rockets release a cloud of flammable liquid into the air around the target, before lighting it up.

"The results are devastating—not only is the explosion significantly longer and the shockwave significantly hotter and stronger than a conventional warhead, but all the oxygen in the near vicinity is also consumed, creating a partial vacuum," Swearingen observed.

It is counted among the most horrifying weapons, especially if the enemy is entrenched in bunkers and caves. The 'blazing sun' will kill its victim either with the intense pressure of the initial blast or suffocate them as their lungs will get ruptured in the vacuum created following the blast. 

The heavy flamethrower system was first used in combat during the Soviet invasion of Afghanistan in 1988 but didn't make its public debut until more than a decade later, during the Second Chechen War in 1999.