Facing Prime Minister’s Questions on Wednesday, Mr Johnson came under fire from the Labour opposition for not going further with measures announced in response to Russia on Tuesday rolling over Ukraine’s border into separatist regions.
Mr Johnson and many other Western leaders have described the action as an “invasion” but are hoping to stave off a “full-scale invasion” deeper into Ukraine territory.
“In light of the increasingly threatening behaviour from Russia and in line with our previous support, the UK will shortly be providing a further package of military support to Ukraine,” Mr Johnson said on Wednesday.
“This will include lethal aid in the form of defensive weapons and non-lethal aid.”
He did not give any details about what the military aid would be but pledged further sanctions against Russia in the form of restrictions on debt and capital raising.
“That will hit Putin where it hurts,” he said.
“But it is absolutely vital that after this first barrage, we work in lockstep with friends and allies around the world and we squeeze him simultaneously — we squeeze him simultaneously in London, in Paris, in New York, at the same time.”
The Prime Minister also revealed Secretary of State for Digital, Culture, Media and Sport Nadine Dorries had asked the UK TV regulator to review the licence of Russian channel RT, formerly known as Russia Today, to broadcast.
Opposition Leader Keir Starmer, amid pushing for harsher sanctions, said the station was Russian President Vladimir Putin’s “personal propaganda tool”.
“I can see no reason why it should be allowed to continue to broadcast in this country,” he told the House.
Mr Starmer pledged Labour’s full support for harsher measures including blocking Russia from financial mechanisms such as the SWIFT money transfer system and a ban on trading in Russian sovereign debt.
Foreign Secretary Liz Truss earlier defended the speed and scale of sanctions against Russia, saying the government was holding some measures in reserve for use in the event of a full-scale incursion into Ukraine.
She told Sky News Western powers wanted to keep some sanctions “in the locker” to deter Mr Putin’s ambitions.
British authorities had said they were seeking to verify troop movements before deciding how to proceed.
“We’ve heard from Putin himself that he is sending in troops,” Ms Truss told Sky.
“We don’t yet have the full evidence that that has taken place. What we are expecting … is a full-scale invasion, including potentially of Kyiv.”
Scotland First Minister Nicola Sturgeon said the government’s sanctions did not fo far enough.
“We’ve heard, rightly and properly, some very tough rhetoric from Boris Johnson in the UK Government in recent weeks,” she said.
“We now need to see that rhetoric matched by action. And that’s important because this is a critical moment for Ukraine but it’s a critical moment for the world
“The choice at this moment in history is to hit Putin hard with the severest of sanctions so that he understands that there will be consequences for his imperialist aggression or we don’t do that and he becomes even further emboldened.”