Kremlin hits back at 'war criminal' slur

The Kremlin has rebuked US President Joe Biden for calling his Russian counterpart Vladimir Putin "a war criminal".

"We believe such rhetoric to be unacceptable and unforgivable on the part of the head of a state whose bombs have killed hundreds of thousands of people around the world," Putin's spokesman Dmitry Peskov was reported as saying on Wednesday by Russian news agencies TASS and RIA Novosti.

Biden made the accusation about Putin to reporters while announcing an additional $800 million in US security assistance to Ukraine to fight Russia, with the new package including drones and anti-armor systems. The United States has pledged a total of $13.6 billion in overall aid to Ukraine.

He was asked at the White House by a reporter if he considered Russia's president a "war criminal". Initially, Biden responded "no", but then he asked the journalist to clarify the question and said: "Oh, I think he is a war criminal."

Biden's use of the term came after the US Senate unanimously passed a resolution on Tuesday calling Putin a "war criminal".

White House press secretary Jen Psaki, who has been sanctioned by Russia, said on Wednesday there was a separate legal process run by the State Department to determine war crimes and that was being carried out.

Biden also accused the Russian military of bombing hospitals and apartment buildings, actions which Moscow has denied.

Putin stressed that Russian forces "are working with modern high-precision weapons", hitting only military targets.

Theater blaze

Ukraine claimed on Thursday that Russia had destroyed a theater harboring more than 1,000 people in the besieged southern port city of Mariupol, with the toll as yet unknown.

Ukrainian officials posted images that appeared to show the once-gleaming whitewashed three-story theater hollowed out and ablaze, with bricks and scaffolding piled high.

Mariupol Mayor Vadym Boichenko called the attack a "horrifying tragedy".

The city is a key strategic target for Moscow, potentially linking Russian forces in Crimea to the west and the Donbass region to the east and cutting off Ukrainian access to the Sea of Azov.

Russia's Defense Ministry denied that its forces bombed the city and stated the building was destroyed in an explosion set off by Ukraine's nationalist Azov battalion.

It claimed "peaceful civilians could be held hostage" at the site.

On Wednesday, Putin said he was prepared to discuss neutral status for Ukraine but that the special military operation to "demilitarize and denazify" the country was "going to plan", justified by the need to uphold Russian security.

Putin also gave a televised speech in which he accused the West of trying to divide Russia with lies and criticized "traitors" inside Russia, the BBC reported.

"Of course, they will try to bet on the so-called fifth column, on traitors－on those who earn their money here but live over there. Live, not in the geographical sense, but in the sense of their thoughts, their slavish thinking," Putin said.

"Any people, and especially the Russian people, will always be able to distinguish the true patriots from the scums and the traitors, and just to spit them out like a fly that accidentally flew into their mouths."

Ukrainian President Volodymyr Zelensky said negotiations with Russia were becoming "more realistic", and Russian Foreign Minister Sergey Lavrov said proposals under discussion were "close to an agreement".

In a speech to the US Congress by video on Wednesday, Zelensky appealed for tougher sanctions on Russia and more weapons to help his country, repeating a request for a no-fly zone over Ukraine, something the West fears would worsen the conflict.

Agencies contributed to this story.