There can be "no durable peace" in Ukraine without the involvement of European nations in any talks to end the war with Russia, the business secretary has told the BBC.
Jonathan Reynolds downplayed divisions between the US and its allies on resolving the conflict, after concerns the Trump administration was moving ahead with peace talks with Russia that would lock out European leaders.
In response, European leaders, including Sir Keir Starmer, are due to hold an emergency summit next week, while US officials are due to meet Russian negotiators.
Reynolds told the Sunday with Laura Kuenssberg programme the UK could act as a "bridge" between the US and the continent to strengthen relations.
Reynolds also told the programme, hosted by Victoria Derbyshire, the UK and Europe had to respond to US demands for them to pay more towards their "collective defence" in the face of "greater threats".
He said the UK government would set out a road map to increase defence spending from 2.3% to 2.5%, but declined to offer a concrete timetable and he said any decision would take into account threats.
Asked if the threat had just got bigger without the US, he said there was "no doubt" that it had.
Reynolds said he thought the UK could "play a constructive role" between the US and Europe over Ukraine.
"I'm not saying it's going to be easy, there's a very assertive agenda from the US."
But he argued Europe and Ukraine would have to be involved for any peace settlement to be lasting.
"Ultimately [President Trump] is somebody who likes to win, and winning would not be rewarding a war of aggression," Reynolds said.
Appearing on the same programme, Conservative shadow foreign secretary Dame Priti Patel said it was "too premature to make assumptions" about the way Ukraine peace talks were heading.