Joe Biden calls Vladimir Putin a 'war criminal' over Russia's invasion of Ukraine

Joe Biden has called Vladimir Putin a war criminal for the first time after Russian forces intensified their offensive against Ukraine and continued to carry out indiscriminate attacks against civilians.

It is the sharpest condemnation of the Russian leader by an American official since the three-week war began, as the White House had previously been hesitant to use the phrase, claiming it was a legal term that required research.

But in a speech on Wednesday, Mr Biden said Russian troops had bombed hospitals and held doctors hostage, as he pledged more aid to help Ukraine fight invading forces.

“He’s a war criminal,” Mr Biden said to a journalist at the White House who asked him if he was ready to use the phrase.

His comments followed Ukraine's President Volodymyr Zelenskyy citing Pearl Harbor and the 9/11 terror attacks as he appealed to US lawmakers to do more to help Ukraine’s fight against Russia.

It came on the day when Mariupol's city council said that Russian forces had bombed a theatre where civilians were sheltering in the encircled port.“We need you right now,” Mr Zelenskyy said in remarks livestreamed at the US Capitol. He added: “I call on you to do more”.

Politicians gave him a standing ovation as he appeared on screen in his now-trademark army green T-shirt.

After describing missiles and airstrikes over Kyiv, President Zelenskyy said: “Please understand us now when we need you. Remember Pearl Harbour, remember September 11, when innocent people were attacked from the air.

"Just like no one else expected it, you could not stop it. Our country, right now, for three weeks now we have the same.”

In another reference to a landmark American event, President Zelenskyy quoted Martin Luther King's 'I have a dream' speech.

“I need to protect our sky... It is the same as when you hear the words I have a dream," he said.

"I wish you to be the leader of the world" - Ukrainian President Volodymyr Zelenskyy

Once again, Ukraine's president called on the US and the West to establish a no-fly zone over his country.

"Is that too much to ask?" He implored, while reasoning that "this is a terror that Europe has not seen for 80 years".

Mr Zelenskyy directly addressed US President Joe Biden in English: "You are the leader of the nation, of your great nation.

"I wish you to be the leader of the world. Being the leader of the world means to be the leader of peace."

Listen to the ITV News What You Need To Know podcast for analysis on the war

Following the Ukrainian president's address, Mr Biden announced that the US is to send more anti-aircraft and anti-tank weapons to Ukraine to assist in its defence against invading forces.

The new assistance includes 800 Stinger anti-aircraft systems, 20 million rounds of small arms ammunition and grenade launchers, along with an unspecified number of drones.

“We’re going to give Ukraine the arms to fight and defend themselves through all the difficult days ahead,” the US President, said.

Mr Biden added that US will be sending an additional $800 million in military assistance, with about $1 billion in aid having already been sent in the past week.

Although substantial military and financial help has been given by America, Mr Biden's administration has stopped short of providing a no-fly zone or the transfer of military jets from neighbouring Poland as the US seeks to avoid a direct confrontation with Russia.

How was the Ukrainian president's address received by Joe Biden and congress? US Correspondent Emma Murphy reports live from Washington

Mr Zelenskyy’s address to the US Capitol is part of a very public strategy, in which the West’s great legislative bodies have become a global stage to orchestrate support against Russia’s crushing invasion.

In a speech to the UK's House of Commons, he invoked Winston Churchill, Hamlet and the power of world opinion. President Zelenskyy has emerged as a heroic figure at the centre of what many view as the biggest security threat to Europe since World War II. Almost three million refugees have fled Ukraine, the fastest exodus in modern times.