A comedian with no political experience has won the most votes in the first round of Ukraine's presidential elections, according to exit polls.

They say Volodymyr Zelensky - who played the president on TV - received 30.4% of the vote, with current leader Petro Poroshenko second on 17.8%.

The two - who have expressed largely pro-EU opinions - are set to take part in a run-off election next month.