According to Joe Biden, there is a “clear indication” that Vladimir Putin may use chemical and biological weapons in Ukraine because his “back is against the wall.”

The US President issued his strongest warning yet that Russia’s leader is considering using both types of weapons in Ukraine’s increasingly bloody conflict.

A UK government minister warned today that the use of chemical or biological weapons by Russian forces in Ukraine would be “unquestionably” a war crime.

Paul Scully, the business minister, told Sky News: “This is Vladimir Putin’s war against Ukraine, the Kremlin’s war. It does not belong to the Russian people. We must ensure that we can make an appeal to the Russian people to put an end to this.”

President Biden’s warning came after days of increasingly nervous briefings from both sides of the Atlantic that Putin could use chemical weapons.

Putin’s “back was against the wall,” he said at a business event.

“Now he’s talking about new false flags he’s setting up, including claiming that we in America have biological and chemical weapons in Europe, which is simply not true,” he added.

“They also claim that Ukraine possesses biological and chemical weapons.” That’s a clear indication he’s thinking about using both.”

Biden also warned businesses to be on the lookout for Russian cyberattacks. In a statement, he said, “It’s part of Russia’s playbook.”

Russia summoned the US Ambassador to Moscow yesterday to protest Biden’s remarks about Putin, saying, “I believe he is a war criminal.”

The Russian embassy in Washington did not immediately respond to a request for comment on the US President’s latest remarks.

It comes as some in the besieged port city of Mariupol bury their neighbours in roadside graves.

Russian artillery continues to shell the eastern cities of Kharkhiv, Sumy, and Chernihiv, while shells hit a shopping centre in the capital Kyiv on Sunday evening, killing at least eight people.

According to the United Nations, nearly 6.5 million people have been displaced from their homes. On Monday, over 8,000 people were evacuated.

More than four weeks into their invasion, Russian troops have yet to capture a major Ukrainian city.

They are increasingly using air strikes, long-range missiles, and artillery to devastate residential areas.

Russian forces were expected to continue attacking critical infrastructure with “high-precision weapons and indiscriminate munitions,” according to a statement from Ukraine’s armed forces.

On March 10, Boris Johnson stated that he “fears” Russia will use chemical weapons in Ukraine.

After Western officials, the US, and Foreign Secretary Liz Truss raised concerns about chemical weapons in the last 24 hours, the Prime Minister was the most senior figure to sound the alarm.

“I’ll make you one other prediction, by the way, which is that the stuff you’re hearing about chemical weapons is straight out of their playbook,” he told Sky News’ new show Beth Rigby Interviews.

“They begin to claim that their opponents or the Americans have stored chemical weapons.”

“And so when they themselves deploy chemical weapons, as I fear they may, they have a sort of… fake story ready to go.

“You’ve seen it in Syria, you saw it even in the UK.”

Asked if that is what he expects next, the Prime Minister replied: “I just note that that is what they’re already doing – it’s a cynical, barbaric government I’m afraid”.