At least 22,000 civilians have been killed during the 3-month siege of Mariupol, the city of Ukraine’s Donetsk region, Pyotr Andryushchenko, adviser to the head of Mariupol, told CNN.

According to him, these numbers are based on the calculations of the officials who stayed in the city.

The adviser asserted that there are difficulties in the burial of the dead people: people whose relatives were killed need to record a video as if they were killed by Ukrainian soldiers.

Andrushenko stated that the local citizens are not allowed to move freely because special entrance documents are required for any movement in the city: “Filtration system doesn’t let them escape from there”.