UK Edition 
Ukraine has lost contact with soldiers defending Mariupol’s stronghold of Azovstal as Kyiv said Russian troops were storming the last pocket of resistance in south-eastern Ukraine.
“Unfortunately, we have lost touch with the guys and we can’t know if they are safe or not,” Vadym Boichenko, Mariupol’s mayor, said on Ukrainian TV on Wednesday.
Ukrainian MP David Arakhamia said Russian troops had entered the territory of the steelworks, which has withstood days of heavy shelling and artillery strikes.
In drone footage filmed by Moscow-backed eastern Ukrainian separatists, the factory was seen being pounded by what appear to be thermobaric bombs.
It comes as a Russian-announced ceasefire is due to begin on Thursday at the besieged steel plant to allow civilians to flee.
Sergei Shoigu, the Russian defence minister, said Ukrainian soldiers were “safely blocked” inside the plant.
His ministry released video footage showing howitzers firing in the distance at what they said were targets at Azovstal.
Meanwhile, evidence of possible war crimes in Mariupol is emerging even though all of the city except for Azovstal is now in Russian hands.
An investigation by the Associated Press published on Wednesday estimated that the bombing of Mariupol’s main theatre in March killed some 600 people.
Drawing on witness testimony, the theatre’s floor plans and photos taken inside the building, AP concluded that the number of casualties is likely to be twice as much as previously thought.
Evacuation after months underground
Several hundred people are still believed to be hiding in the maze of underground bunkers at Azovstal, though around 100 were earlier safely evacuated and arrived in central Ukraine on Tuesday.
Azovstal - one of Europe’s biggest steelworks, dominating the skyline of the coastal city of Mariupol - felt like home for Elyna Tsybulchenko, who worked in quality control at the factory for years.
But she had no idea she would have to live in an underground bunker there for two months.
In early March, the plant worker and her family took shelter at Azovstal after incessant Russian airstrikes hit her home and cut off the city of almost 500,000 people from all utilities.
After making a perilous two-day journey by one of the dozen buses evacuating the first group of civilians trapped at Mariupol’s besieged plant, a sobbing Ms Tsybulchenko said: “Every night we went to sleep thinking if we would survive and wake up or not.”
A total of 101 people, who had not seen daylight for two months, were finally able to leave Azovstal’s bunkers at the weekend in a rescue operation mediated by the United Nations and the International Committee of the Red Cross.
It took the convoy two days before it arrived in Zaporizhzhya, 140 miles north-west of Mariupol. The evacuees had to pass through 26 Russian and separatist-controlled checkpoints, before spending hours being interrogated at a Russian “filtration camp”.
Iryna Vereshchuk, Ukraine’s deputy prime minister, who coordinated the operation and met the evacuees at a sprawling car park near a shopping centre in Zaporizhzhya, said several hundred people remain trapped at Azovstal. Kyiv would not rest before it gets them out, she said, adding: “We are not going to leave anyone who wants and can be saved.”
The evacuees were offered food and shelter in Zaporizhzhya before continuing their journey elsewhere in Ukraine or Europe. They spoke of surviving on meagre rations inside the dark and damp bunkers underneath the plant.
Food supplies at the bunker started to run out in the first few weeks of the war, as ever more people flocked to the maze of underground shelters that appeared to be the only safe place in a city pummelled by Russian aviation and encircled by Russian troops.
When soldiers from the Azov battalion, defending the city, brought a bag of flour, one woman started to bake bread. Yulia, a mother of two, told Ukrainian television: “The bread would be sliced in tiny pieces. It was such happiness when we saw that bread. And that smell - it’s as if you were walking past a bakery.”
Ms Tsybulchenko, who came to the bunker on March 2 with her husband, daughter and son-in-law, said her daughter would stave off hunger by frying flour with salt.
A four-year-old sleeping near them in the bunker would beg his mother for food, Ms Tsybulchenko remembered. The boy’s mother tried to trick him by saying he did not eat that much before the war and reminding him of the foods he used to hate. “Now, I like everything!” he would reply.
Cut off from the rest of the world, the bunker residents got their news from the Azov soldiers, who would show them drone footage of the carnage outside.
“When they were coming in, we would run around and ask: ‘How can we get out? What happened at this or that address?’” said Ms Tsybulchenko.
She added that her daughter did not want to upset her and told her that she saw the photos of their block, completely destroyed, only when leaving Mariupol.
Footage filmed by Azov showed the civilians crawling out from the bombed-out entrance of one of the bunkers, to find scenes of utter destruction.
“It was an apocalypse, no less,” Ms Tsybulchenko said of what she saw on her way out of the city.
On Tuesday evening, evacuees slumped back in the seats of the buses, visibly exhausted. Others would step out of the bus and shield their faces from television cameras, too tired to speak.
Inside a sprawling tent at the Zaporizhzhya shopping centre’s car park, volunteers were handing out food and basic necessities.
A young mother sat at a picnic table with a toddler on her lap, feeding him spoonfuls of porridge as he played with a brand-new toy - a stuffed cow. Elderly women nearby were eating rice and pork chops from plastic plates.
Two weeks ago, Anna Zaitseva, who has a six-month-old son, was filmed by Azov in the underground bunker, begging the world community to negotiate an evacuation.
“Raising a child is tough. It’s even tougher in a bunker with no light,” said Ms Zaitseva, with her long blonde hair in a ponytail, cradling Svyatoslav in her sling.
She thanked the military for managing to bring her baby formula and extra rations of food.
“When the formula ran out, we found semolina and tried to cook it. We boiled water over a candle,” she said, fighting back tears.
Getting out of the bunker had for weeks been too dangerous, as Russian forces kept pounding the plant.
“To find water, we had to move between buildings,” she said. “The men did that for us, including my dad. He was wounded, but thank god it wasn’t serious.”
The evacuees made a gruelling journey to the west of Mariupol, where they spent a night before they were taken to Berdyansk, another port city that is under Russian occupation. There they underwent humiliating body checks, were fingerprinted and had their phones checked, several residents told Ukrainian media.
At some checkpoints, soldiers tried to trick evacuees into revealing their loyalty to Ukraine, one Mariupol resident told The New York Times.
Russian officials have insisted that filtration camps were necessary, as they wanted to prevent Azov batallion troops - whom they describe as Nazis - from escaping. “At one checkpoint they yelled: ‘Glory to Ukraine,’ to see whether we would yell: ‘Glory to the heroes,’ though, of course, we knew that would end badly,” the evacuee said, referring to a patriotic greeting that has taken on a special significance since the invasion.
Kateryna, who left Mariupol with her two sons, said she was interrogated by Russian forces.
“They have been asking all the time about the military, about the depth of the bunkers, our whereabouts. Women married to military men were told that (the Russians) would find them and send them their husbands’ heads in a box.”
Ms Vereshchuk said the Russian troops detained a female police officer with her child and would not let her leave to the Kyiv-controlled area. She said Ukraine would be fighting for her release.