G7 countries are expected to announce an "international framework for Ukraine's long-term security arrangements" on the margins of the NATO summit in Vilnius on Wednesday, the U.K. government said in a statement.
The statement matched a similar announcement by the White House.
"The joint declaration, expected to be signed by all members of the G7, will set out how allies will support Ukraine over the coming years to end the war and deter and respond to any future attack," the U.K. statement said.
Prime Minister Rishi Sunak said: "As Ukraine makes strategic progress in their counteroffensive, and the degradation of Russian forces begins to infect Putin's front line, we are stepping up our formal arrangements to protect Ukraine for the long term."