Vitali Klitschko told German media Russia wants to occupy all of Ukraine and is threatening Baltic states. The former WBO heavyweight champion was speaking amid scepticism among some Germans over Berlin supplying heavy weapons to Ukraine.
Mr Klitschko, in comments translated to English, said: "They want all of Ukraine. They are talking about Baltic States. They are talking about rebuilding the Russian Empire.
"And therefore, for many sceptics, the Russians will go as far as we will let them. Therefore we need common positions. "We all want to live in peace. Therefore we must unite all countries. It is up to us to re-establish peace in Ukraine and Europe."
Kyiv's mayor was speaking on the sidelines of the World Economic Forum at the Swiss Alpine resort Davos....