Is it a cluster bomb, illumination flares or something else?
Since these shouldn’t be illumination flares that do not burst but burn for a few minutes and whose use in daylight conditions it’s at least weird, the one depicted in the footage appears to be the series of exploding cartridges of a cluster bomb.
Watch by yourself:
In particular, according to some of our readers, these could be submunitions of an RBK-250 or 500 cluster bomb.
Once ejected from the RBK container incendiary ZAB-2.5 fall down burning. In this case, there is only a quick mid-air burst that could be the visual effect of the ignition of the ZAB 2.5Ms rocket: once accelerated by the rocket, the submunitions can penetrate in the ground and then explode (from 0 to several minutes after the impact).
@TheAviationist These are ZAB 2.5M submunitions of RBK-500 CLUSTER BOMBs.
— Babak Taghvaee (@BabakTaghvaee) 4 Ottobre 2015
However, there is no evident sign of impact of the incendiary submunitions with the ground, therefore it could be a cluster bomb for anti-personnel shrapnels or flechettes (or something else, like mines or even leaflets). Any other guess?
H/T @JulianRoepcke for discovering this video and @BabakTaghvaee for the analysis