The mayor of Ukraine’s second largest city was fighting for his life yesterday after an assassination ­attempt for which the Kremlin was blamed.

Hennadiy Kernes, mayor of Kharkiv, the only major city in the east where the insurgency has made no headway, was shot in the back while out exercising. The murder attempt came on a day when the United States imposed sanctions on a Russian oil baron who is one of President Putin’s closest allies.

Mr Kernes, a “mini-oligarch” with an alleged criminal past and a fondness for posting topless pictures of himself on social networks , beat Ukraine’s interior minister to the mayoralty by a margin of less than 1 per cent four years ago.

During the protests against Viktor Yanukovych, the deposed