An ambulance drives in downtown Kyiv, Ukraine, Thursday, March 17, 2022, as a 35 hour curfew in the Ukrainian capital comes to an end. Russian forces destroyed a theater in Mariupol where hundreds of people were sheltering Wednesday and rained fire on other cities, Ukrainian authorities said, even as the two sides projected optimism over efforts to negotiate an end to the fighting. (AP Photo/Vadim Ghirda)© ASSOCIATED PRESS An ambulance drives in downtown Kyiv, Ukraine, Thursday, March 17, 2022, as a 35 hour curfew in the Ukrainian capital comes to an end. Russian forces destroyed a theater in Mariupol where hundreds of people were sheltering Wednesday and rained fire on other cities, Ukrainian authorities said, even as the two sides projected optimism over efforts to negotiate an end to the fighting. (AP Photo/Vadim Ghirda)Zelenskiy said late on Wednesday: “Citizens of Russia, how is your blockade of Mariupol different from the blockade of Leningrad during world war two? … We will not forget anyone whose lives were taken by the occupiers.”

Between 1941 and 1944, German forces encircled and starved Leningrad, now called St Petersburg, leading to the deaths of hundreds of thousands of people.

Zelenskiy said it was still unclear how many had died or been injured in the airstrike on a theatre in the city where hundreds of displaced people were believed to have been sheltering. Russia has also been accused of a strike on a swimming pool where pregnant women and young children had gathered and of shelling a convoy of cars carrying civilians fleeing the city. “Our hearts are broken by what Russia is doing to our people,” he said.

This photo released by Donetsk Regional Civil-Military Administration Council on Wednesday, March 16, 2022 shows the Drama Theatre, damaged after shelling, in Mariupol, Ukraine.© Donetsk Regional Civil-Military Administration Council via AP This photo released by Donetsk Regional Civil-Military Administration Council on Wednesday, March 16, 2022 shows the Drama Theatre, damaged after shelling, in Mariupol, Ukraine.Early on Thursday, one person was killed and three injured by a Russian missile attack on a residential building in Kyiv, Ukraine’s emergency services reported. Rescuers received a report of a building on fire in the Darnytsky district at 5.02am and found the 16th floor of the building was “demolished” and on fire.

The southern port city of Mariupol has been facing a humanitarian catastrophe for days, and Russia continued its attacks on it and other Ukrainian cities on Wednesday, even as the two sides continued efforts at peace talks to negotiate an end to the fighting.

In this image from video provided by the Ukrainian Presidential Press Office and posted on Facebook, Ukrainian President Volodymyr Zelenskyy speaks from Kyiv, Ukraine, on Wednesday night, March 16, 2022. (Ukrainian Presidential Press Office via AP)© ASSOCIATED PRESS In this image from video provided by the Ukrainian Presidential Press Office and posted on Facebook, Ukrainian President Volodymyr Zelenskyy speaks from Kyiv, Ukraine, on Wednesday night, March 16, 2022. (Ukrainian Presidential Press Office via AP)Earlier, the US president voiced his view that his Russian counterpart was a war criminal, marking a significant change in his language. Kremlin spokesperson Dmitry Peskov, said Biden’s comments were “unacceptable and unforgivable rhetoric”, according to Russia’s state-owned Tass news agency.

In other developments:

  • The US is to send an additional $800m in security assistance to Ukraine, including 800 anti-aircraft systems, 9,000 anti-armour systems, 20m rounds of ammunition and drones. The move came after Zelenskiy pleaded with Congress to do more, invoking the painful memories of Pearl Harbor and the September 11 terrorists attacks and echoing Martin Luther King’s call for a more peaceful future. Biden said afterwards that Ukrainians “have shown remarkable courage and strength in the face of brutal aggression”.
  • Zelenskiy is to address Germany’s pa
  • rliament on Thursday morning, a
  • nd said he would “fight for ever greater support for Ukraine, for even greater pressure on Russia”.
  • The UN security council will meet Thursday at the request of six western nations. The UK’s UN mission tweeted: “Russia is committing war crimes and targeting civilians. Russia’s illegal war on Ukraine is a threat to us all.” The meeting comes ahead of an expected vote on a Russian humanitarian resolution that has been sharply criticised for making no mention of Ukraine.

In Mariupol, the city council said was a “bomb on a building where hundreds of peaceful Mariupol residents were hiding.” “We don’t know if there are any survivors,” one witness said. “The bomb shelter is also covered with debris … there are both adults and children there.”

About 1,000 civilians were allegedly hiding inside the theatre, which was designated as a shelter for the displaced, including children and elderly people.

Rescuers work at a site of a residential building damaged by an airstrike, as Russia's attack on Ukraine continues, in Kyiv, Ukraine, in this handout picture released March 17, 2022.  Press service of the State Emergency Service of Ukraine/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.© Thomson Reuters Rescuers work at a site of a residential building damaged by an airstrike, as Russia’s attack on Ukraine continues, in Kyiv, Ukraine, in this handout picture released March 17, 2022. Press service of the State Emergency Service of Ukraine/Handout via REUTERS ATTENTION EDITORS – THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.Later Pavlo Kyrylenko, the head of Donetsk regional administration, claimed Russians had also targeted the Neptune swimming pool. “Now there are pregnant women and women with children under the rubble there,” he said in a post on Telegram. “It is impossible to establish the number of casualties from these strikes.”

A witness who posted a video of the aftermath of the attack said the pool had been destroyed and efforts were under way to rescue one pregnant woman trapped in the rubble.

Moscow denies targeting civilians and Russia’s defence ministry said its forces had not struck the building, RIA news agency said.

A satellite photograph from 14 March and released on Wednesday by Maxar Technologies showed the word “children” in large Russian script painted on the ground outside the red-roofed theatre building.

Ukraine’s ministry of defence has described Mariupol as the worst front of the war. Mass graves have been dug on the outskirts of the city and the bodies of men, women and children have been left on the streets. More than 400,000 of its inhabitants are either without or with dwindling access to running water, food and medical supplies.

Local officials have said more than 2,500 have been killed. But the reality is that, because of the shelling, the dead cannot be counted.

Ukrainian officials also accused Russian forces of shelling a convoy of cars of civilians fleeing the city, wounding at least five people, including a child.

Local officials shared photos and videos of the aftermath of the alleged attack. “Heavy artillery of the enemy forces fired on a convoy of civilians moving along the highway towards Zaporizhzhia,” the governor of the region, Oleksandr Starukh, said in an online post.

More than 400 people, whom Ukrainian authorities have compared to hostages, remain trapped in a Mariupol hospital seized by Russian forces.

“It is impossible to get out of the hospital,” one employee said on the Telegram social media platform. “They shoot hard, we sit in the basement. Cars have not been able to drive to the hospital for two days. High-rise buildings are burning around … Russians rushed 400 people from neighbouring houses to our hospital. We can’t leave.”

Officials have told families to leave their dead outside in the streets because holding funerals is too dangerous.

Witnesses tell of a city in chaos, under constant bombardment, which is becoming more and more difficult to escape. Thousands of people are trying to reach the city of Zaporizhzhia, where refugees are taking shelter, but according to the Ukrainian authorities, the Russians are trying to prevent citizens from fleeing.

Taking Mariupol, which is 34 miles from Russia’s border, would mark a strategic breakthrough for Vladimir Putin.

The city lies between territory held by Russian-backed separatists in the Donbas region and the Crimean peninsula, which was annexed by Moscow in 2014 and from where it has launched its assault on key southern towns in Ukraine.