Zelenskiy says Russia wages 'terror', Mariupol says thousands deported

Ukrainian President Volodymyr Zelenskiy said Russia's siege of the port city of Mariupol was "a terror that will be remembered for centuries to come", while local authorities said thousands of residents there had been taken by force across the border.

"Over the past week, several thousand Mariupol residents were deported onto the Russian territory," the city council said in a statement on its Telegram channel late on Saturday.

The council also said Russian forces bombed a Mariupol art school on Saturday in which 400 residents had taken shelter, but the number of casualties was not yet known.

Reuters could not independently verify the claims.

Russian news agencies have said buses have carried several hundred people Moscow calls refugees from the strategic port on the Sea of Azov to Russia in recent days.

Air raid sirens sounded across major Ukrainian cities early on Sunday but there were no immediate reports of fresh attacks.

Some 400,000 people have been trapped in Mariupol for more than two weeks, sheltering from heavy bombardment that has severed central supplies of electricity, heating and water, according to local authorities. 

Rescue workers were still searching for survivors in a Mariupol theatre that local authorities say was flattened by Russian air strikes on Wednesday. Russia denies hitting the theatre or targeting civilians. 

On Friday, Russia's defence ministry said its forces were "tightening the noose" around Mariupol and that fighting had reached the city centre.

In a late night broadcast, Zelenskiy said the siege of Mariupol would "go down in history of responsibility for war crimes".

"To do this to a peaceful city... is a terror that will be remembered for centuries to come."

Still, he said, peace talks with Russia were needed although they were "not easy and pleasant".

The U.N. human rights office said at least 847 civilians had been killed and 1,399 wounded in Ukraine as of Friday. The Ukrainian prosecutor general's office said that 112 children have been killed.

Russian forces have taken heavy losses since Feb. 24, when President Vladimir Putin launched what he calls a "special operation" aimed at demilitarizing Ukraine and purging it of what he sees as dangerous nationalists. Ukraine and the West say Putin launched an aggressive war of choice.

Long columns of troops that bore down on the capital Kyiv have been halted in the suburbs.

Ukraine's military said Russian forces did not conduct offensive operations on Saturday, focusing instead on replenishing supplies and repairing equipment. It also said Ukrainian air defences shot down three Russian combat helicopters.

Zelenskiy said the Ukrainian front line was "simply littered with the corpses of Russian soldiers."

Reuters could not independently verify the situation on the ground.

In Syria, some paramilitary fighters say they were ready to deploy to Ukraine to fight in support of their ally Russia but have not yet received instructions to go. 

On Saturday, Russia said its hypersonic missiles had destroyed a large underground depot for missiles and aircraft ammunition in the western Ivano-Frankivsk region. Hypersonic weapons can travel faster than five times the speed of sound, and the Interfax agency said it was the first time Russia had used them in Ukraine. 

A spokesperson for the Ukrainian Air Force Command confirmed the attack, but said the Ukrainian side had no information on the type of missiles used.