"Too many countries are saying this is a European war that is unnecessary ... and so the pressure will grow to encourage - coerce, maybe - the Ukrainians to a bad peace," he told broadcasters in the Rwandan capital Kigali, where he is attending a Commonwealth summit.

Johnson said the consequences of Russian President Vladimir Putin being able to get his way in Ukraine would be dangerous to international security and "a long-term economic disaster".

(Reporting by Andrew MacAskill; Writing by David Milliken; Editing by Pravin Char)