Amnesty International has concluded that the Russian airstrike on a theatre in the Ukrainian city of Mariupol in March constituted a war crime.
The human rights organization spent three months gathering evidence on the atrocity and has now presented its findings in a report released Thursday.
Among the evidence presented in its findings are some 52 witness statements, 28 of which were made by people who were inside or near the theatre at the time of the strike.
"After months of rigorous investigation, analysis of satellite imagery and interviews with dozens of witnesses, we concluded that the strike was a clear war crime committed by Russian forces," said Agnès Callamard, Amnesty International's secretary general.
The organization concluded it was almost certain that Russian fighter aircraft dropped two 500-kilogram bombs on the building as civilians took shelter there on March 16.
Amnesty determined that at least 12 people were killed in the airstrike and many more were seriously injured.
The number of fatalities given by Amnesty was lower than previous estimates as a large number of people reportedly left the theatre in the days ahead of the attack.
Most of those who remained took refuge in the basement of the theatre or in other parts of the building where they managed to avoid the full force of the blast, the report said.
Thousands of civilians in Mariupol are believed to have lost their lives during the relentless Russian airstrikes that took place during the siege of the city, which finally ended in mid-May when it fell to the Russian military.
