Drone footage reportedly shows barrages of Tos-1A "heavy flamethrower" thermobaric warheads targeting Ukrainian frontline fighting positions in the vicinity of Kupiansk in Ukraine's eastern Kharkiv region.

Kupiansk is a main railway junction in the region, so it makes a prime tactical target for the Russian military which relies heavily on trains for resupply.

The TOS-1 thermobaric rockets are incredibly powerful fuel-air bombs or vacuum bombs, which combust the oxygen around the target, resulting in a massive fiery explosion. The TOS-1 220mm 30-barrel multiple rocket launcher systems (MLRS) is mounted on a T-72 tank chassis, and due to its limited firing range, it is not considered artillery, but rather a frontline fire support asset.