The head of the United Nations human rights monitoring mission in Ukraine said on Tuesday that the death toll in Ukraine is “thousands higher” than official figures.

       At a press briefing in Geneva, Matilda Bogner, head of the UN Human Rights Monitoring Mission in Ukraine said that thousands more civilians had been killed in the country since the war began, with actual numbers exceeding its official death toll of 3,381.

       “We have been working on estimates, but all I can say for now is that it is thousands higher than the numbers we have currently given to you,” Ms Bogner said after a trip to Ukraine last week where she visited areas around Kyiv and Chernihiv previously occupied by Russian forces.

       The United Nations team, which includes 55 monitors in Ukraine, said most of the deaths were caused by explosive weapons with a wide impact area such as missile and airstrikes.

       She added that the “big black hole” is really Mariupol where it has been difficult to fully access and get fully corroborated information.

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       Mariupol - a port city on the Sea of Azov, has endured the most destructive fighting of the war in Ukraine. Up to 98 per cent of all Mariupol buildings have been obliterated, Verkhovna Rada, Ukraine’s parliament said on the Telegram messaging app.

       The elderly, women and children embrace after fleeing the horrors in Mariupol - a port city on the Sea of Azov

       (James Elder UNICEF)

       Kyiv says it is likely that tens of thousands of people have been killed there since Russia’s unprovoked invasion started on 24 February. Moscow denies targeting civilians.

       The Azovstal steel plant is understood to be the last part of the city still held by Ukrainian fighters.

       In addition to the military, at least 100 civilians remain in the (Azovstal) shelters.

       “However, this does not reduce the intensity of attacks by the occupiers,” Mariupol mayoral aide Petro Andryushchenko wrote on the Telegram messaging app.

       Ukraine said Russian forces were bombing a steelworks in Mariupol on Tuesday where a local official said at least 100 civilians were still holed up with the last fighters defending the strategic southern city.

       The Russians have cut off access making it difficult to transport food supplies, and medicine, including water, to civilians and fighters trapped behind.

       The Azov Regiment, which is holding out in Azovstal, said on Telegram that in the past 24 hours, 34 Russian aircraft had flown over the plant including eight sorties by strategic bombers. It said the plant had come under fire from the Russian navy and from tanks, artillery fire and rockets.

       In the latest appeal for help in saving lives in Mariupol, the head of the Ukrainian Orthodox Church urged Putin to let more civilians and fighters leave the city.

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       Last week Unicef spokesperson James Elder wrote all elderly people, women and children have been evacuated from the steelworks.

       Includes reporting by agencies