The cluster bomb is a terrifying weapon. Dropped from a plane or fired from a rocket, the bomb bursts open and spills dozens of small sub-munitions. These tiny bomblets then explode over a wide area and are more likely to kill civilians than other kinds of munitions are — largely because unexploded bomblets linger for years after a conflict. Several international treaties ban their use, which neither Russia nor Syria have signed.

Now, it looks as though Moscow’s military might be using a new type of cluster bomb in Syria. Human Rights Watch first reported these new advanced cluster bombs on Oct. 11. It’s important to note that HRW was unable to confirm whether these new types of weapons are actually cluster bombs or if Russia even launched them. But evidence supporting the theory is mounting on social media, and several independent journalists and observers have called the munitions out for what they seem to be — cluster bombs. FULL REPORT