David Lammy, the UK foreign secretary, is to visit the western Ukrainian city of Lviv today.
He will join his Ukrainian counterpart and 17
other foreign ministers, the Foreign Office said.
They will discuss how to secure peace in Ukraine.
Ministers will confirm their support for the “establishment of a Special Tribunal for the Crime of Aggression against Ukraine”, the Foreign Office said.
In addition, the UK is providing almost £25m in “new funding to support local Ukrainian organisations” in protecting the most vulnerable.
Lammy said: “I have been supportive of a Special Tribunal to prosecute Russia’s leaders for their war of aggression since March 2022, just weeks after Putin’s full-scale invasion.
“This was a key manifesto commitment and as soon as we came into government, we made it a top priority.”