Andy Burnham has hit back at Moscow's claim that Britain has added fuel to the fire of the Ukraine war, asking: "Who started the fire?"
Britain's decision to supply more long-range missiles and drones to Ukraine has drawn warnings of retaliation from the Kremlin.
On Monday, Vladimir Putin's spokesman Dmitry Peskov said plans to provide Ukraine with blueprints for long-range Scalp missiles would add "fuel to the fire" and undermine any chance of peace.
Prime Minister responds in Kyiv
Asked about his comments on a visit to Kyiv, the Prime Minister told reporters: "Who started the fire? That's the question, isn't it?"
Mr Burnham's visit to Ukraine, his first foreign trip as Prime Minister, coincides with the 35th anniversary of the country's independence from the Soviet Union.
Ahead of the visit, he announced that the UK would provide Kyiv with blueprints for British components used in the French-produced Scalp missile as Paris looks at setting up assembly lines for the weapon in Ukraine.
Missile plans and Russian warnings
The Scalp weapon is a version of the British Storm Shadow missile, which the UK has already provided to Ukraine, and can be used to hit more targets within Russia itself.
Responding to the announcement, Russian foreign minister Sergei Lavrov said his country had a right to regard the "direct involvement of British missile forces" as "participation in the war, with all the ensuring consequences".
But in a speech outside Kyiv's St Sophia cathedral on Monday, Mr Burnham vowed he would not be deterred from providing aide to Ukraine.
He said: "Despite Russia's outrageous threats to my country, we will continue our support for Ukraine."
Independence day address
During his speech marking Ukraine's independence day, he praised the "sheer strength" of the Ukrainian people and described their country as "Europe's protector, not a drain on our security, but the front line in keeping Europe safe".
Mr Burnham went on to compare Ukraine's resistance to Russia to the UK's fight with Nazi Germany, saying: "My nation kept the flame of European freedom alive in the 20th century, you hold that flame in the 21st."
He travelled to Kyiv earlier on Monday, making his first foreign trip since becoming Prime Minister in July in an effort to underline the UK's support for Ukraine.
During Monday's event in Kyiv, Ukrainian president Volodymyr Zelensky presented Mr Burnham with an award recognising the UK's support.
Coalition meeting and domestic strife
In his own independence day speech, Mr Zelensky said Ukraine would "not submit" to Russia, saying: "Ukrainians will not be cobblestones under the feet of tsars and rulers."
Later, Mr Burnham is expected to chair his first meeting of the Anglo-French-led "coalition of the willing" and hold a meeting with Mr Zelensky, who was the first foreign leader to visit 10 Downing Street under his premiership.
The coalition meeting is expected to focus heavily on Ukraine's need for more interceptor missiles as Russia continues its bombardment of the country.
Ukraine has run short of interceptors in recent months, with much of the world's stocks being diverted to the Middle East following the outbreak of the Iran war.
Mr Burnham's visit comes as Mr Zelensky faces domestic political strife caused by a rift with his former defence minister, Mykhailo Fedorov, who was sacked last month after reportedly falling out with the head of Ukraine's armed forces.
Mr Fedorov, whose dismissal triggered weeks of mass protests, has called for Mr Zelensky to hold elections, arguing democracy "should not be the hostage of Putin".
He has also called for Mr Zelensky to face questions over what he knew about alleged corruption in his inner circle.
Last week, Ukraine's anti-corruption authorities said they had uncovered a money-laundering plot, leading Mr Zelensky to sack one of his senior officials over their alleged involvement.
The president has denied any involvement, telling reporters over the weekend: "The heads of anti-corruption agencies have zero questions for me. They understand perfectly well that I am not involved in anything like that."
