There is a growing body of evidence on mass graves in the besieged city of Mariupol in Ukraine, the United Nations (UN) said on Friday, adding that one of the mass graves could contain as many as 200 corpses.

“We have got increasing information on mass graves that are there,” Matilda Bogner, the head of the UN human rights team in Ukraine, told reporters via a video call on Friday, adding that some of the evidence came from satellite images of the besieged port city.

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Bogner went on to say that at least 1,035 civilians had been killed in Ukraine since the Russian invasion began on February 24, and added that she and her team were probing indiscriminate attacks not just by Russian forces, but by Ukrainian forces too.

The news of the supposed mass graves in Mariupol comes at a time when Russia has intensified its bombardment of the southern port city, which is a crucial port in the Sea of Azov and has tremendous strategic value.

Since the siege of Mariupol began, Ukraine has accused Russia of indiscriminately bombing civilian targets in the city, including a maternity hospital and a theatre that was housing more than 1,000 women and children.

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At the time of writing this article, reports suggested that as many as 300 were feared dead in the bombed theatre, which, if true, would make the airstrike on the theatre the deadliest attack on civilians since the invasion began.

In light of growing evidence of Russian attacks on civilians and the use of banned weapons such as thermobaric bombs and cluster munitions, several international probes have been launched to determine whether Russian troops in Ukraine are guilty of war crimes.