UK Prime Minister Keir Starmer told EU leaders in Paris that he would consider deploying UK troops to Ukraine in the event of a lasting peace agreement.
Meanwhile, the US and Russia have been holding talks in Saudi Arabia aimed at ending the war, but Ukraine was not invited.
A full-scale Russian invasion sparked the war in Ukraine almost three years ago, eight years after it unilaterally annexed Crimea.
The BBC’s Analysis Editor Ros Atkins has been looking at what that would mean.
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