The deal is at the heart of Kyiv's push to win over Donald Trump's robust support as the U.S. president strives to reach a rapid end to the war with Russia that Ukraine's supporters fear could come at the expense of its national interests.

Ukraine has agreed the terms of a major minerals deal with the US, a senior official in Kyiv has told the BBC. "We have indeed agreed it with a number of good amendments and see it as a positive outcome," the official said, without providing any further details.