That was the case in Kiev, as incumbent President Petro Poroshenko was the only one to appear onstage for a televised debate. His chief rival, TV comedian Volodymyr Zelensky, did not attend the event, at Olympic Stadium.

The two men will face in a runoff election this week, after neither garnered enough of the vote in a previous election to win the presidency outright. Poroshenko got just 16 percent of the vote in the March 31 first round of elections. Zelensky was the leading vote-getter, with more than 30 percent of the vote. In all, 38 candidates were on the ballot. The candidate with the third-most votes was former prime minister Yluia Tymoshenko. Since that first election, Zelensky, who is known for playing a president on television, has made few public appearances and has campaigned largely using social media.

Poroshenko criticized his rival and then answered question for the audience. After 45 minutes, he left the stage.

Poroshenko was elected to a five-year term in 2014, after the ouster of President Viktor Yanukovych during what has teen termed the Ukrainian Revolution. An experienced statesman, Poroshenko was previously Minister of Foreign Affairs and Minister of Trade and Economic Development. He has been embroiled in political controversies of late.

Zelensky is a political novice who is perhaps most well-known for his role as the Ukrainian president in the TV show Servant of the People. The main character, Vasyl Holoborodko, begins as a schoolteacher with no political experience but emerges as a strong national leader. The show has been on the air for nearly four years and routinely garners an audience of half of the country's population of 42 million. He has also starred in movies, including the Russian-language hit Love in the Big City.

Ukraine has also suffered through five years of a civil war of sorts, with intervention by troops of neighboring Russia in the Donbass region, in Ukraine's eastern part.