But Trump has given no indication he is prepared to offer assistance to ensure any agreement holds. European promises to re-arm — the president has been telling the continent to stop freeriding on US guarantees for the best part of a decade — may have come too late.

The euro jumped on Monday as investors eyed the prospects of a peace deal in Ukraine and potential increases in defence spending across the euro area.

European leaders closed ranks Sunday in support of Kyiv at a London summit, where they pledged to spend more on security and assemble a coalition to defend any truce in