Cluster strikes by Russia on Ukraine's second-largest city amount to war crimes, according to human rights organisation Amnesty International.
Dozens of indiscriminate strikes on Kharkiv used widely banned cluster munitions, the human rights organisation said in a report, killing hundreds of civilians and injuring thousands since the start of the invasion in February.
The campaign group wants all perpetrators to be brought to justice under international law.
Cluster munitions and scatterable mines
Amnesty International said that "during an extensive investigation" they had found evidence of Russian forces repeatedly using 9N210/9N235 cluster bombs and scatterable mines – both of which are subject to international treaty bans because of their indiscriminate effects.
Researchers from the human rights organisation documented seven strikes in different areas of Kharkiv, where they found fins and pellets of 9N210 or 9N235 cluster munitions and fragments of 220mm Uragan rockets.
Each rocket contains 30 individual munitions that have a "frag sleeve" consisting of pellets made from chopped steel rods.
According to Amnesty, at each location, the researchers found multiple impacts, including distinctive spalling – fragments that are broken off – on the ground, consistent with the expected damage from 9N210/9N235 cluster munitions.
Doctors from two hospitals in Kharkiv reportedly showed the Amnesty International researchers the distinctive pellets which they had removed from patients injured in cluster bomb strikes.
Cluster bombs are inherently indiscriminate. Rockets release dozens of submunitions in mid-air, scattering them indiscriminately over an area that could measure hundreds of square metres.
Cluster munitions have a high dud rate, with a high percentage failing to explode on impact, effectively then becoming land mines, which pose a threat to civilians long after deployment.
For these reasons the use – as well as production, stockpiling, and sale or transfer – of cluster munitions is prohibited under the 2008 Convention on Cluster Munitions (CCM), which 110 countries have joined.
Neither Russia nor Ukraine are parties to the CCM, but they are obliged to respect the ban on the use of inherently indiscriminate weapons that forms part of customary international humanitarian law.
Russian forces have also used another type of munition against residential neighbourhoods in Kharkiv, one that combines the worst attributes of cluster munitions and of anti-personnel land mines: the PTM-1S, a small, scatterable anti-personnel mine.
Scatterable mines such as these, which can be activated by individual people, are banned under the 1997 Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction.