Zelensky pleads with the UN to 'save all the wounded from Azovstal' as Kremlin ...

Ukrainian President Volodymyr Zelensky today appealed to the head of the United Nations to asked help 'save' the lives of the remaining wounded Ukrainians under siege at the Azovstal steel plant in the decimated city of Mariupol.

'The lives of the people who remain there are in danger. Everyone is important to us. We ask for your help in saving them,' Zelensky told Antonio Guterres by phone, after thanking him for the successful evacuations earlier this week led by the UN and Red Cross. 

He called on the UN to 'assist in the removal of all the wounded from Azovstal', civilians and soldiers alike.

Zelensky's call with Guterres came as Russia said its forces would cease fire on the plant and open a humanitarian corridor for civilians for three days beginning Thursday.

'The Russian armed forces will from 8am to 6pm Moscow time (0500 GMT to 1500 GMT) on May 5, 6 and 7 open a humanitarian corridor from the territory of the Azovstal metallurgical plant to evacuate civilians,' the defence ministry said on Wednesday.

'During this period, the Russian armed forces and formations of the Donetsk People's Republic will unilaterally cease any hostilities,' the statement read, adding that civilians sheltering at the plant will be allowed to travel to Russia or Kyiv-controlled territory.

Mariupol has endured near constant bombardment since the first week of the war and Ukrainian authorities believe upwards of 20,000 civilians have likely been killed there.

A small contingent of Ukrainian fighters are still holed up in the Azovstal plant along with up to 1,000 civilians, but the rest of the city is under Russian control.

There was a brief respite in the shelling over the weekend and Monday, which allowed more than 100 civilians to evacuate via buses to Ukraine-controlled territory northwest near Zaporizhzhia. 

But shelling commenced yet again on Tuesday as Ukraine accused Moscow of launching a 'powerful' assault on the industrial zone.

The mayor of Mariupol Vadym Boychenko said that contact had been lost with Ukrainian forces holed up in the plant amid 'heavy fighting' with Russian troops.

The Russian army meanwhile said it had restarted its bombing campaign on Azovstal because Ukrainian troops had used the pause in fighting to regroup and take up combat positions.

More than 100 people - including elderly women and mothers with small children - left the rubble-strewn Azovstal steelworks on Sunday and set out in buses and ambulances for the Ukrainian-controlled city of Zaporizhzhia, about 140 miles to the northwest, according to authorities and video released by the two sides.

At least some of the civilians were apparently taken to a village controlled by Russia-backed separatists. The Russian military said that some chose to stay in separatist areas, while dozens left for Ukrainian-held territory.

In the past, Ukraine has accused Moscow's troops of taking civilians against their will to Russia or Russian-controlled areas, a claim the Kremlin has denied.

Before the weekend evacuation, overseen by the United Nations and the Red Cross, about 1,000 civilians were believed to be in the plant along with an estimated 2,000 Ukrainian defenders. Russia has demanded that the fighters surrender, but they have refused.

As many as 100,000 people overall may still be in Mariupol, which had a prewar population of around 450,000. 

Heart-wrenching footage emerged yesterday of terrified and exhausted Ukrainian civilians being evacuated from Azovstal.

The clips were captured by Ukraine's Azov battalion and give harrowing insight into the conditions endured by the civilians holed up in the factory, many of whom shared their thoughts on the conflict and the impact of the Russian invasion. 

'There are more than ten children from 10 to 12 years old in our bunker alone,' one woman said as her child sobbed into her chest.

'A few more bombs and our bunker will be no more... you can imagine the mental condition of the children.'

Another evacuee expressed fear among civilians that they would be shipped off to Russian-controlled regions instead Ukraine-held Zaporizhzhia, as has happened to many internally-displaced Ukrainians in the Donbas region.

'There are a lot of children here, a lot of women. If everything goes well, civilians will leave.... A lot of people are still here, they're afraid to go because there are no guarantees they will be taken to Zaporizhzhia as promised.'

Others spoke of their desperation simply to make it to any part of Ukraine not under Russian control, and claimed it was impossible to even attempt leaving prior to the brief ceasefire due to daily bombing campaigns.

The final clip shared by the Azov battalion showed a bus full of evacuees driving away from the steel plant, presumably to relative safety in Zaporizhzhia.

But instead of relief or elation, the passengers were overwhelmed with sadness, bursting into tears as they witnessed the destruction around them. 

More pictures emerged late last night and early this morning of some of the evacuees arriving in Zaporizhzhia, suggesting that the UN and Red Cross-led evacuations were largely successful.

Moment Russia uses 'thermobaric warheads' to devastate Azovstal plant: Communications are lost with heroic last defenders of Mariupol a day after Russian troops began storming the steel works Communication has been lost with the last Ukrainian soldiers defending Mariupol, the exiled mayor has said  Comes a day after commander said Russians were storming Azovstal plant with tanks, troops and armour  New video shows the plant being bombarded with what appear to be lung-crushing thermobaric rockets  If Azovstal is captured then it would put Russia in full control of Mariupol, the largest city to fall during the war 

ByChris Pleasance for MailOnline

Communications have today been lost with the last heroic defenders of Mariupol holed up inside the Azovstal steel works, after Russian forces stormed the complex.

Vadym Boichenko, mayor of the besieged city, said there is 'heavy fighting' ongoing inside the plant today and that he had 'lost contact' with those inside.

There is no way of knowing 'what's going on, whether they are safe or not,' he said.

The grim news came as footage emerged showing Russian forces using what appeared to be lung-crushing thermobaric rockets to bombard Azovstal as tanks and troops moved into the sprawling industrial zone.

Footage released by the so-called Donetsk People's Republic today showed lines of rocket artillery cutting through factories and warehouses that sit in the centre of Mariupol and are the last redoubt of the city's beleaguered defenders.

Russia appears to to be trying to seize Azovstal despite Vladimir Putin announcing last month that he had called off the operation to preserve the lives of his troops.  

News that communications have been lost will raise fears for the safety of hundreds of civilians thought to be inside, just days after 100 were rescued during a ceasefire.

Ukraine had been calling for the ceasefire to be extended so that all civilians could be removed, but Russia accused Kyiv's troops of 'taking advantage' of the break in fighting to set up new defensive positions and resumed bombing yesterday.