Has ISIS damaged a Russian base in Syria?

Russia denied a report that ISIS partly destroyed one of its important military bases in Syria.

The US global intelligence company Stratfor released a series of images that purport to show damaged aircraft and supply depots at the base.

It added that the “attack, and the considerable losses on the Russian side, stress the continued threat to supply lines for Russia and regime forces.”

"A range of separate locations within the airfield were targeted very accurately, with no sign of damage in the areas separating them," it said. "A single accidental explosion would not have been able to have this result."

Four Russian combat helicopters and around 20 supply trucks were destroyed at the base which is strategically located in central Syria between war-ravaged Palmyra and Homs.

Stratfor says the images show the damage incurred was likely not accidental. And, according to agencies, a website affiliated with ISIS said on May 15 that terror group hit the strategic T4 base in central Syria.

But U.S. officials said they believe that it was likely the result of an accidental fuel tank explosion.

Watch also: The military airplanes used by Russia in Syria