Boris Johnson has described Russia’s invasion of Ukraine as a “catastrophe for our continent” as he prepares to unveil fresh sanctions against Moscow.

The prime minister will make an address to the nation this morning after explosions were heard in Ukrainian cities as Russia launched a military offensive.

He will also speak to fellow G7 leaders and is calling for an urgent meeting of all NATO leaders as soon as possible following Russia’s latest aggression against its neighbour.

At about 5pm, Mr Johnson will also address the House of Commons where he is expected to give details of more punitive measures on Russia.

Explosions near major cities including capital Kyiv – Ukraine latest

Key developments at a glance:
• Explosions heard in major cities including Kyiv and Kharkiv
• Shelling in western city of Lviv reported by Ukrainian emergency service
• Ukraine says Russia has launched a “full-scale invasion” and “war of aggression”
• Vladimir Putin ordered a “military operation” in Ukraine’s Donbas region
• Joe Biden says US and its allies will respond amid global condemnation
• EU drawing up ‘unprecedented’ sanctions

PM to unveil ‘unprecedented sanctions’ as Russian ambassador summoned

Foreign Office minister James Cleverly told Sky News the UK would bring forward “an unprecedented level of sanctions” with the aim it will “hopefully persuade the people around Vladimir Putin this is completely the wrong thing to do”.

Cabinet Office minister Stephen Barclay, also the PM’s chief of staff, said Mr Johnson would unveil “overwhelming sanctions” later.

These are likely to be coordinated with the US and EU, as well as other Western allies.

Meanwhile, Foreign Secretary Liz Truss summoned the Russian ambassador to meet with her on Thursday to “explain Russia’s illegal, unprovoked invasion of Ukraine”.

Mr Johnson chaired a meeting of the government’s emergency COBRA committee at 7.30am on Thursday morning following a call with Ukrainian President Volodymyr Zelenskyy.

“The PM said he was appalled by the unfolding events in Ukraine,” a Downing Street spokesperson said.

“The Ukrainian president updated the PM on the attacks taking place, and the PM said the West would not stand by as President Putin waged his campaign against the Ukrainian people.

“The PM said he hoped Ukraine could resist and that Ukraine and its people were in the thoughts of everyone in the UK people during this dark time.”

Labour leader Sir Keir Starmer has called for the “hardest possible sanctions” to be taken against “all those linked to Putin”.

“There will be dark days ahead,” he said. “But Putin will learn the same lesson as Europe’s tyrants of the last century: that the resolve of the world is harder than he imagines and the desire for liberty burns stronger than ever.”

Senior Tory calls for NATO air support for Ukraine

PM previously announced a “first tranche” of sanctions against Russia on Tuesday after Mr Putin initially ordered his troops to move into two separatist regions in eastern Ukraine.

Those sanctions targeted five Russian banks and three oligarchs, freezing their UK assets and banning travel to Britain.

However, the package was met with a lukewarm response in the Commons with many MPs – including senior Conservatives – calling on the PM to go further and faster in punishing Mr Putin’s regime and those close to it.

Following Russia’s fresh action against Ukraine in the early hours of Thursday, Tory ex-cabinet minister David Davis called for NATO countries to provide air support to the Ukrainian army.

“Whether we like it or not Putin has effectively declared war on the West,” the former Brexit secretary posted on Twitter.

“While we should continue to impose the most ferocious sanctions they are no longer a deterrent. They are a punishment. They will not stop him.

“If NATO does not act now, Ukraine will be defeated in a matter of days.”

Mr Davis admitted it was “far too late to get boots on the ground”, but added: “It is not too late to provide air support to the Ukrainian army, which may neutralize Putin’s overwhelming armoured superiority.”

Fellow Conservative MP Alicia Kearns also said the UK should “look to deploy air strength to protect Ukrainian air space to prevent mass casualties”.