Volodymyr Zelenskyy
© Valentyn Ogirenko / ReutersVolodymyr Zelenskyy
An initial joint national exit poll predicts comic actor Volodymyr Zelenskyy will win the first round of Ukraine's presidential election with 30.4 percent of the vote, ahead of the incumbent Petro Poroshenko with 17.8 percent.

The poll puts former Prime Minister Yulia Tymoshenko third with 14.2 percent.

If the polling data are confirmed by official results, Zelenskyy and Poroshenko will advance to a runoff on April 21.

Zelenskyy, who stars on a TV comedy series about a teacher who becomes president after a video of him denouncing corruption goes viral, has tapped into public frustration in Ukraine over the pace of reforms and fighting corruption.

Poroshenko has fought to integrate the country with the European Union and NATO, while strengthening the military which is fighting Russia-backed separatists in the east of the country.

Ukrainians and outsiders hope the eventual winner can bring much-needed stability and reform to a country that is a key transit route for Russian gas and an ally in Western efforts to keep a resurgent Russia in check.

Ukraine's Interior Ministry said it had received more than 1,600 complaints about electoral violations two hours before polls closed.

It said the reported violations included unauthorized campaigning at polling stations, attempts to bribe voters, and removal of ballots.

The Central Election Commission (CEC) said by late afternoon "no systemic violations" had been reported.

"There are isolated instances, but they are classic for any voting process in any election campaign," CEC Secretary Natalia Bernatska told journalists.

By midafternoon, (eds: 3 p.m. local time), more than 45 percent of eligible voters had cast ballots, according to the CEC.