United Kingdom (UK) Prime Minister Andy Burnham said Britain's support for Ukraine was "unwavering" during a visit to Kyiv to mark the country's Independence Day.
Britain announced on Monday it would allow Kyiv access to classified technology to start production of European SCALP long-range cruise missiles in Ukraine, capable of carrying out strikes deep within Russia.
In response, the Kremlin said the use of classified British technology would "add fuel to the fire" of their worsening relations, after it warned London last week there would be "consequences" for supplying drones to Kyiv.
"Who started the fire? That's the question, isn't it? Ukraine did not do that," Burnham said.
"Russia began this illegal invasion, and that is absolutely clear, and they could stop it at any given time," he added.
Burnham later co-chaired a virtual meeting of the "Coalition of the Willing" — a group of countries backing Ukraine — with French President Emmanuel Macron and German Chancellor Friedrich Merz.
The leaders were expected to discuss Ukraine's request for more air defence systems to stop Russian ballistic missiles pounding Ukrainian cities.