Former World Boxing Council [WBC] champion Vitali Klitschko won the election for mayor of Kiev, the country's likely new president said on Sunday.

"I can say with confidence that according to our information Vitali Klitschko will be the new mayor of Kiev," billionaire tycoon Petro Poroshenko said after declaring his own victory in the presidential election.

"I congratulate him," he said at a press conference alongside Klitschko.

The burly 42-year-old heavyweight boxer turned opposition hero had been in the running for the presidency but dropped out of the race in March to support Poroshenko.

Mayoral elections were held in several cities on Sunday in tandem with the presidential ballot.