Russian shelling is so intense that for the last two days Yuri * and 200 other terrified Ukrainian civilians have been trapped in the bunker of the church where they now live in their besieged hometown of Mariupol.

       They are running out of food, and since electricity and water supplies have been cut they are forced to sneak out under heavy fire to draw water from a nearby well.

       Friday lunchtime the bombardment came dangerously close. One shell punched through the roof of the church building, eviscerating the main chapel above ground.

       For the first time in two days the 19-year-old trainee welder, who is with his mother and 11-year-old brother, emerged from below ground to assess the damage, showing videos to The Independent. In the clips the jagged teeth of wooden beams edge the massive hole in the roof. The pews of the chapel and the altar are wrecked.

       He says it was a miracle none of the families, who are running out of supplies, were seriously injured.

       “We are under constant mortar shelling and one of the shells hit our church. There are 200 of us living here,” he says with desperation, via an encrypted messaging app during a rare spell of connection in the besieged city.

       An explosion in an apartment building that came under fire from a Russian army tank in Mariupol

       (AP)

       He adds that a second shell hit a house nearby which is still on fire.

       “It’s hell here. Imagine 200 people sitting in one room for two days. We can’t even breathe fresh air.

       “I can’t go out into the street, because [shrapnel] fragments are flying everywhere and machine gunfire is constant. There is shooting every two minutes.”

       The Independent has managed to reach people who are living under intense bombardment in the besieged coastal city, which Ukrainian Red Cross officials say is suffering the worst humanitarian crisis in the entire country.

       It is effectively surrounded and there is no way out. Attempts to create humanitarian corridors have failed for five days in a row, aid agencies say. Around 200,000 people are thought to still be stuck without power or water within the city that is strategically important for the Russians as it lies along the coast and is a gateway to other northern and western parts of the country.

       Those inside the city or displaced residents whose relatives remain trapped inside, paint an apocalyptic picture. In the worst hit parts, they say to get water families are reduced to tapping the now-defunct radiators in their homes or melting snow to get water.

       This map shows the extent of Russia’s war in Ukraine

       (Press Association Images)

       Under relentless Russian shelling, rocket and gunfire, they are forced to break into shops to scavenge food.

       In temperatures that are well below zero, they burn whatever they have in little piles outside their homes to cook and keep warm.

       “Yesterday two of my friends were killed, they were travelling with three others in a car that was hit by a shell,” Yuri continues with desperation.

       “The car exploded and they burned inside it.”

       According to the mayor’s office in Mariupol more than 1,500 have been killed in the city in the last two weeks, although The Independent was unable to verify that number.

       The mayor himself released a video a few days ago from a bunker saying that Russia was bombing the city every 30 minutes. He claimed humanitarian corridors were being mined and shelling was preventing people from leaving.

       Aid group Doctors Without Borders, have said that some residents are dying for lack of medication, while others killed in the fighting are being buried in makeshift graves by their neighbours. The local authorities said Russia shelled a mosque sheltering 80 people over the weekend.

       On Saturday it was reported that Russian forces had shelled a mosque in the city where some 80 people including children were seeking safety. Ukraine’s foreign ministry tweeted: “The mosque of Sultan Suleiman the Magnificent and his wife Roxolana (Hurrem Sultan) in Mariupol was shelled by Russian invaders.

       “More than 80 adults and children are hiding there from the shelling, including citizens of Turkey.”

       It’s hell here. Imagine 200 people sitting in one room for two days. We can’t even breathe fresh air

       Yuri, a resident of Mariupol

       A strike on a maternity hospital last week that killed three people sparked international outrage and war-crime allegations.

       Russian officials have repeatedly denied targeting civilian infrastructure and made several contradictory claims about that hospital including that it had been taken over by far-right Ukrainian forces to use as a base and then that it was emptied of patients and nurses. They have also denied deliberately striking humanitarian corridors.

       But Maksym Dotsenko, head of the Ukrainian Red Cross, told The Independent all their efforts to evacuate the city have so far failed because of Russia’s bombardment.

       “We cannot help those in Mariupol. We have tried to organise evacuation convoys every day but are unsuccessful,” he said.

       “They are completely cut off. We cannot even send in a single truck of food.

       Ukrainian officials said there was supposed to be another attempt at an evacuation corridor on Saturday but residents who have fled the city say they had little hope this would happen.

       Mary, a 27-year-old IT business analyst, says she escaped with her 16-year–old brother on 3 March after a missile landed in their backyard and the water and heating were cut off. Even then she tells The Independent, the route was being shelled as she tried to leave.

       Her parents Svetlana, 50 and Sergei 55 remain trapped in the city. Mary can only speak to them for a minute or two every few days when they get mobile phone signal.

       She last heard from them a few days ago and doesn’t know if they are still alive.

       She shared the audio of that last conversation. They sound frail and frightened on the line.

       Mariana Vishegirskaya lies in a hospital bed after giving birth to her daughter Veronika, in Mariupol

       (AP)

       “Four times we have tried to leave and four times the humanitarian corridor was cancelled,” her mother says, her voice cracking.

       “Fighter jets are flying overhead, we hear bombs falling from the aircraft, but we don’t know what areas they are attacking, because there is no mobile phone connection.”

       The situation is desperate, her mother Svetlana continues.

       “We try to share both cereals [bread] and water. We try to help children. We try to help the elderly. Of course there’s no water, no gas, no heating, no light.”

       In the messages she says the eastern side of a river that cuts Mariupol in half was “a humanitarian catastrophe”. It lies closer to Russian forces.

       Helena, who fled Mariupol for another part of Ukraine, showing messages from people still inside the city

       (Bel Trew)

       “We can’t get there at all, we don’t know the condition of the river crossing,” she adds.

       “People are sitting there without gas, they can’t go out of their basements because they are shooting in the streets. It is very difficult, we need help. Pay attention to Mariupol,” she finishes before bidding her daughter goodbye.

       Mary says her parents told her civilians were reduced to breaking in and looting shops to get supplies.

       “There is no electricity so people are keeping food outside in the snow. There is no heating, it’s freezing,” Mary adds.

       In the central city of Vinnystia, a key crossroad on the refugee trail, families that have fled Mariupol, are now living in the dorm rooms of a school turned into an informal displacement camp.

       They rely entirely on the humanitarian handouts to survive. Their reports from inside Mariupol echo Mary’s and Yuri’s accounts.

       Helena escaped 12 days ago with her son, his wife and her three grandchildren. Relatives who thought the fighting would stop, stayed put and are now missing.

       “Twenty people from my extended family are still in the city, we haven’t been able to get through to them for five days,” says Helena, 61 in floods of tears, sitting next to two of her grandchildren on a camp bed.

       “Everything is being hit. A missile fell onto a building and mother and her daughter were trapped under the rubble. We understand the girl died from thirst because there are not enough diggers to get them out in time.”

       Olisiya and her young child. They fled Mariupol earlier in the war

       (Bel Trew)

       Back in Mariupol, Yuri sends a video he took from his bunker, where in the pitchblack the constant stutter of gunfire sounds in the background. He says everyone at the church is desperate to escape to safety.

       “We want to leave, but every time we have tried, heavy shelling has erupted,” he writes before signing off for the night.

       “And so for now we are stuck here. My only message is that we are grateful to God that everyone has so survived.”