Russian soldiers are holding patients and doctors hostage at a Mariupol hospital, claimed a regional governor, amidst a brutal siege.
Parents have also been forced to leave premature babies in a hospital in the Ukrainian city with around 350,000 people trapped with food and water running out, say reports.
Horrific scenes of bombed out buildings and street fighting have been played out in recent days as the Russian army shells the city and the Ukrainian residents are ready to battle to the death to keep them out.
Desperate attempts have been made to evacuate the city as part of a humanitarian corridor but there remain about 350,000 people still inside Mariupol with resources dwindling.
And with the fighting raging, people have been unable to leave hospital, said Pavlo Kyrylenko, head of the Ukrainian military in the Donetsk region.
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He also claimed that around 400 local residents and 100 staff had been rounded up as human shields and are being kept at the hospital in what he called “crimes against humanity”.
"It's impossible to get out of the hospital," Mr Kyrylenko wrote in a Telegram post. "They're shooting hard, we sit in the basement."
He continued: "Cars can't drive to the hospital for two days already. High-rise buildings are burning around. Russians drove 400 people from neighbouring houses into our hospital. We can't get out."
In hospital three in Mariupol there are premature babies without parents who have been forced to leave, it is reported.
It comes as Ukraine accused Russia of blocking a convoy trying to take supplies to the besieged city, where the Red Cross said desperate families were being "suffocated" as food and water ran out.
Deputy Prime Minister Iryna Vereshchuk said hundreds of civilians managed to leave Mariupol in cars for the second successive day, but the aid convoy trying to reach the port city was stuck at nearby Berdyansk as Russian shelling continued.
"Our side ensures a complete ceasefire," she said. "Russia, as usual, is cynically lying, thinking that people and the world do not see it and do not understand."
Russia denies targeting civilians and has blamed Ukraine for the repeated failure to establish safe passage for civilians and humanitarian convoys since it invaded Ukraine on February 24.
Mariupol residents have been without heating, electricity and running water for most of the past two weeks, and at least 200,000 are in urgent need of evacuation, according to official Ukrainian estimates.
Vereshchuk said the majority of residents do not have cars, so there was a need for buses to reach the city in convoys so that they can be evacuated.
Residents are "essentially being suffocated in this city now with no aid," Ewan Watson, spokesperson for the International Committee of the Red Cross (ICRC), told a UN briefing in Geneva.
The ICRC said on Twitter that "tens of thousands of families are living under the constant threat of danger" in Mariupol.
"They're huddled in whatever shelter they can find. They have limited food and water. They're terrified," it said.
Russian forces agreed on Monday to allow the creation of a humanitarian corridor out of Mariupol. The first evacuation convoy then left, after more than a week of failed attempts to do so, but Ukrainian officials were unable to deliver any aid.
About 300 civilians have reached the city of Zaporizhzhia, about 140 miles from Mariupol, the Mariupol city council said.
At the same time about 2,000 cars had left Mariupol and a further 2,000 were waiting to leave, it said.
More than 2,500 Mariupol residents have been killed since the Russian invasion, a Ukrainian official said on Monday.
