A desperate gun battle near Palmyra, Syria, has claimed the lives of two Russian pilots.

The two men had attacked a troop of ISIS fighters in the Homs region on Friday. In midst of the operation, their Syrian Mi-25 helicopter ran out of ammunition, the Russian Defense Ministry reported, according to Interfax.

“The turning helicopter was hit by militants’ gunfire from the ground and crashed in the area controlled by the Syrian government army. The crew died," it added.

Video footage published on Saturday by ISIS's news agency Amaq showed a helicopter being shot and crashing to the ground against cries of 'It's fallen, God is great'.

Russian forces entered the Syrian war toward the end of last year, backing the forces of Syrian President Bashar al-Assad.