Boris Johnson has condemned the “unconscionable” targeting of fleeing civilians at an eastern Ukraine railway station by Russia.
The UK’s leader said the attack showed “the depths” that the Russian military has sunken to.
Also, the Prime Minister announced the UK will send another £100m in military equipment to Ukraine as well as unveiling plans to work with Germany to reduce reliance on Russian oil and gas.
Speaking at a major press conference with Germany’s chancellor, Olaf Scholz, Mr Johnson said the two countries “will also agree on weaning ourselves off dependence on Russian oil and gas and ensuring that our energy security cannot be threatened by a rogue state.”
He said: “This is not easy for any of us, and I applaud the seismic decisions taken by Olaf’s government to move Germany away from Russian hydrocarbons.
“Today we have agreed to maximise the potential of the North Sea and collaborate on energy security and on renewables where Germany and the UK lead the way on new technology.
“We cannot transform our respective energy systems overnight, but we also know that Putin’s war will not end overnight.”
He said the UK would send another £100m of high-grade equipment to Ukraine including anti-aircraft missiles, another 800 anti-tank missiles, and precision munitions.
As part of the countries’ co-operation, both leaders said they will hold a joint cabinet meeting.
Germany’s leader Olaf Scholz said the images from Bucha and other places were “shocking” and he said Putin bears responsibility for the war crime of killing civilians.
He called upon Russia to “finally agree to a ceasefire” and open safe, humanitarian corridors for civilians and said his country’s strategy was to impose “dramatic” costs on Russia in sanctions.
Germany has faced criticism for its reliance on Russian energy but Mr Scholz vowed more steps to wean his country from Russian gas.
“We’re not going to import coal anymore, and I’d like to use this opportunity to clearly state that Germany is already starting to wean off its dependence [on Russian energy],” he said.
“We’re investing large-scale in order to establish the technical and physical infrastructure necessary to import natural gas via the northern German shores.
"We're also going to make sure with legal measures so that there are no legal difficulties implementing our decisions quickly”.
Asked whether he could defend the EU sending billions to Russia for its fossil fuels, Mr Scholz replied: “To give you a very clear answer - we are doing all we can, and we’re doing a lot”.
However he admitted the task was “not easy”.
Asked whether he felt a sense of shame over the “blood money” being sent to Russia for gas payments, he said it was not “feasible” to get gas elsewhere in the amounts needed with current infrastructure.
“This is something for engineers and billions of investments ... We’re optimistic that we will get rid of the need to import gas from Russia soon”, he said.
Meanwhile, Boris Johnson told reporters he has not spoken to Putin since the invasion began.
“I think that negotiating with Putin does not seem to me to be full of promise. I don't feel that he can be trusted,” he said.
“That's not to say I don't admire the efforts of people who try to find a way through, but my own view is that I am deeply, deeply sceptical and, I'm afraid, cynical now about his reassurances."
