Moscow is accused of being behind an airstrike on an art school used to shelter hundreds of civilians, and of forcibly sending Mariupol residents to Russia.
Authorities in the besieged Ukrainian port of Mariupol made further claims of Russian atrocities on Sunday, as fighting reportedly continued inside the city where thousands of people remain trapped.
The finger has been pointed at Moscow for an alleged airstrike which flattened an art school where hundreds of civilians were said to be sheltering, and for thousands of alleged forced deportations to Russia.
Local authorities said the art school’s building was destroyed and people could remain under the rubble.
"Yesterday (Saturday), the Russian occupiers dropped bombs on the G12 art school located on the left bank of Mariupol, where 400 Mariupol residents -- women, children and the elderly -- had refugees," the local authority said in a statement posted on Telegram.
Access to Mariupol is impossible: the attack has not been confirmed and there was no immediate word on casualties.
The alleged bombing follows other attacks on prominent civilian buildings.
Last Wednesday Russian forces bombed a theatre in the city where people were sheltering. City authorities said 130 people were rescued but many more could remain under the debris.
The previous week a strike on a maternity hospital left three people dead including a child, the authorities said.
Mariupol residents 'forcibly deported' to Russia — unverified claims
The city council in Mariupol made another claim on Sunday — alleging that Russian soldiers have forcibly relocated several thousand city residents, mostly women and children, to Russia.
The governor of the Donetsk region, Pavlo Kirilenko, also accused Moscow of having "forcibly deported more than 1,000 inhabitants of Mariupol" living in the east of the city to Russia, without specifying when the alleged relocations took place.
Kirilenko said Russian forces have set up "filtration camps" where they "check the telephones" of Mariupol inhabitants before "confiscating their identity documents". "Then they are sent to Russia," he said on Facebook, adding that "their fate on the other side (of the border) is unknown".
The claims by both the governor and Mariupol council have not been verified.
Another unverified claim, from a Ukrainian lawmaker, says those deported are being taken for forced labour in remote parts of Russia.
Inna Sovsun told Times Radio that according to the mayor and city council in Mariupol, they are being taken to so-called "filtration camps" before being "relocated to very distant parts of Russia, where they’re being forced to sign papers that they will stay in that area for two or three years and they will work for free in those areas".
Evacuations reported despite bombardments
Russian news agencies have said buses have carried several hundred people Moscow calls refugees, from the southeastern port to Russia in recent days.
The vast majority of people trying to flee the fighting have looked to move west to more peaceful parts of Ukraine, or abroad.
Mariupol authorities said on Sunday that nearly 40,000 people have fled over the past week — almost 10% of its population — using more than 8,000 personal vehicles to leave via a humanitarian corridor via Berdyansk to Zaporizhzhia.
A group of 19 children — mostly orphans — who had been stranded in a sanitorium in Mariupol, was evacuated to Donetsk, authorities said on Sunday. Aged between four and 17, they had spent two weeks in the frozen basement having been sent to the city from eastern Ukraine before the latest Russian offensive.
Russian State TV on Sunday broadcast video which it said showed people preparing for evacuation from Mariupol. According to the rebel Donetsk government, over 500 people left the city, including 114 children.
Several efforts have been made to create humanitarian corridors to evacuate people from the bombarded and besieged city. On Saturday Ukraine's deputy prime minister described the latest attempt as "partially operational".
'Terror will be remembered for centuries' — Zelenskyy
Ukrainian President Volodymyr Zelenskyy said the siege of Mariupol would go down in history for what he said were war crimes committed by Russian troops. “To do this to a peaceful city, what the occupiers did, is a terror that will be remembered for centuries to come,” he said in a video address early on Sunday.
A presidential adviser said earlier that there was no immediate military help for the city, saying the nearest forces able to assist were already struggling against Russian forces at least 100 kilometres away.
Mariupol is surrounded by Russian troops and has been cut off from energy, food and water supplies.
Russian forces have already cut Mariupol off from the Sea of Azov, and its fall would link Crimea, which Russia annexed in 2014, to eastern territories controlled by Moscow-backed separatists.