NATO “will respond” if Russian President Vladimir Putin uses chemical weapons, US President Joe Biden has said.

Asked if the alliance would take military action, Mr Biden said: “It would trigger a response in kind.

“You’re asking whether NATO would cross… we’d make that decision at the time.”

Speaking after meetings of NATO and the G7, he said: “The nature of the response will depend on the nature of the use.”

Ukraine war live updates: 1,000 individuals and businesses now sanctioned

Other key developments:

• Ukraine’s navy claims it has destroyed Russia’s large landing support ship Orsk, near the port city of Berdyansk
• UK Foreign Secretary Liz Truss announces 65 new Russian sanctions
• Russia’s deputy UN ambassador tells Sky News Moscow would use nuclear weapons if ‘provoked’
• The UK has promised to send Ukraine 6,000 anti-tank and high explosive weapons
• At least 1,035 Ukrainians have died and 1,650 been wounded, according to the UN, while UNICEF says more than 3.6 million have fled the war – half of them children

The US and its allies have previously said they are concerned Russia might resort to using Chemical weapons as its invasion struggles against Ukrainian resistance, with Mr Biden saying it was a “real threat”.

Chemical weapons use would be ‘catastrophic’ for Putin

Addressing what would happen if Mr Putin deployed weapons of mass destruction, UK Prime Minister Boris Johnson said: “You have to have a bit of ambiguity about your response, but I think it would be catastrophic for him if he were to do that, and I think that he understands that.”

But he said Mr Biden was right to warn about the threat, adding: “When the Russians start doing stuff about ‘there are factories in Ukraine producing American biological weapons’, you know that is a prelude to a false flag operation.”

NATO Secretary General Jens Stoltenberg echoed his concerns, saying: “We are concerned partly because we see the rhetoric and we see that Russia is trying to create some kind of pretext accusing Ukraine, the United States and NATO allies of preparing to use chemical and biological weapons.”

A similar tactic has been used in Syria, where the Russia-backed regime has often sought to blame the rebels it is fighting when it has been accused of using chemical weapons against its own people.

Mr Stoltenberg said if chemical agents were used they could spread across the border, affecting one of its member states.

NATO leaders also agreed to send Ukraine protective equipment to defend itself against biological, chemical and nuclear attacks.

White House sets up special team to plan for potential attack

The White House has set up a team of national security officials to plan for what happens if Russia uses chemical or biological weapons in Ukraine, a senior administration official said.

White House national security adviser Jake Sullivan sent a memo 28 February describing how the so-called “Tiger Team” would consider what could happen over the next three months of conflict, the official told NBC News.

Scenarios under discussion were said to have included: Russia using chemical or biological weapons; Russia targeting US convoys carrying weapons to Ukraine; the global food supply being disrupted; and the refugee crisis.

Russia is among 193 countries who have signed the Chemical Weapons Convention, a treaty that bans their development, production or use.