Kadyrov's Chechens celebrate the capture of Mariupol (VIDEO)

Mariupol Kadyrov Chechens

With the Ukrainian military and Azov Battalion besieged in Azofstal plant in Mariupol, Chechen leader Ramzan Kadyrov posted a video to social media of his soldiers celebrating their capture of the city.

The video, which is already making the rounds on the internet, shows Chechen fighters holding flags and shouting "Allahu Akbar".

FT's Moscow Bureau Chief Max Seddon wrote on Twitter: "Russia's 'liberation' of Mariupol looks like this, according to Ramzan Kadyrov's Telegram channel."

Russian President Vladimir Putin proclaimed the "liberation" of the southeastern port city by Russian forces -- even as he called off an attempt to storm the Azovstal steel plant, the final bastion of Ukrainian defenders inside the city

Ukrainian officials, who maintain the city remains contested, have warned of a major humanitarian emergency in Mariupol as food and water run out, with electricity and gas cut -- but several attempts to establish evacuation corridors to allow civilians to escape have failed.

"Unfortunately, it is not possible today to evacuate civilians from Azovstal," Boichenko, the city's mayor, said Thursday. "Because we are asking for a stable ceasefire. Somewhere we need one day to be able to accommodate those residents who have been hiding there for 57 days in a row, and they are being bombed, bombed and bombed."

Speaking from the Azovstal plant - the last part of Mariupol not under Russian control - Svyatoslav Palamar from the neo-Nazi Azov Battalion said defenders had repelled waves of Russian attacks.

"I always say that as long as we are here, Mariupol remains under control of Ukraine," he said.

Putin called off a planned Russian assault on the steelworks - a maze of tunnels and workshops - and ordered his troops to seal it off instead.

"Block off this industrial area so that a fly cannot pass through," he said.

Much of Mariupol has been destroyed in weeks of heavy Russian bombardment and intense street fighting. Taking the Sea of Azov port is a key Russian war aim and would release more troops to join a Russian offensive in the eastern Donbas region.

"All the buildings in the territory of Azovstal are practically destroyed. They drop heavy bombs, bunker-busting bombs which cause huge destruction. We have wounded and dead inside the bunkers. Some civilians remain trapped under the collapsed buildings," Capt Palamar said.

He said that civilians were in separate locations away from fighters. They were in basements containing 80-100 people each but it was unclear how many civilians there were in total as some buildings had been destroyed and fighters could not reach them because of shelling. Entrances to some of the bunkers were blocked by heavy concrete slabs that only heavy machinery could move, he said.

"We keep in touch with those civilians who stay in places that we can get to. We know that there are small children there as young as three months old," he said.

The fighter appealed for civilians to be given safe passage out of the steelworks and called for a third country or an international body to act as a guarantor for their safety.

"These people have got through a lot already, through war crimes. They don't trust Russians, and they are scared," he said, adding that they feared torture and murder at the hands of Russian troops or deportation to Russia through so-called filtration camps.

Elderly civilians in the steelworks were in need of medicine while there were also about 500 seriously wounded fighters who were not getting the care they needed - including major surgery such as amputations.

"After 52 days of blockade and heavy fighting we are running of medicines. And then we also keep unburied bodies of our fighters whom we need to bury with dignity in Ukraine-controlled territory," he said.

Up to 120,000 ethnic Greeks live in Mariupol and its surrounding villages.

READ MORE: Who is the Pontian Greek fighting in Mariupol against the Azov Battalion?