KYIV -- Ukrainians are voting in a second-round presidential election that could seal the political fate of incumbent President Petro Poroshenko.
Polls showed Poroshenko's rival, 41-year-old comedian Volodymyr Zelenskiy, with a substantial lead as campaigning wound down.
A survey released on April 18 by the Reiting research group found that 57.9 percent of voters say they will definitely vote to support Zelenskiy, with 21.7 percent saying they plan to vote for Poroshenko.
AS IT HAPPENS: Our Live Blog Of The Ukraine Vote
Zelenskiy, who has run his campaign mostly on social media and has largely avoided substantial policy discussions, has benefited from Ukraine's slumping economy, endemic corruption, and fatigue over Kyiv's five-year-long war against Russia-backed separatists in parts of eastern Ukraine.
"I'm not a politician," Zelenskiy said during a sometimes-heated debate between the two candidates at Kyiv's Olimpiyskiy Stadium on April 19. "I'm just an ordinary person who has come to break the system."
Ukrainian soldiers vote in a special ballot station in the village of Krymske in the Luhansk region on April 21.
As he cast his ballot, Zelenskiy said his wife, who accompanied him to the polling station, had put him in a good mood ahead of time by playing a song by American rapper Eminem, although he couldn't remember the song.
Zelenskiy told reporters after voting at a polling station in Kyiv that he will hold a press briefing after the results are announced.
"Today will be a victory for Ukrainians, a victory for Ukraine...We have united Ukraine," he said.
Asked by RFE/RL what would be the first issues he would take on if elected president, he answered, "The war and corruption."
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Zelenskiy's Oligarch Connection
For his part, Poroshenko, 53, has tried to play up Zelenskiy's lack of experience, saying he would be unable to stand up to Russian President Vladimir Putin.
"You'd be a weak head of state," Poroshenko told his rival at the April 19 debate, "who would be unable to defend himself from Putin's blows. I don't believe [Zelenskiy] dreams of surrendering Ukraine, of dragging Ukraine back into the Russian Empire, but Putin has such a dream."
Speaking after casting his ballot, Poroshenko said, "It's important to be guided by reason, not laughs," adding that "it could be funny first, but pain may come later."
He emphasized the need to "defend achievements over the past five years," noting the creation of Ukraine's own independent Orthodox Church, which he championed.
"For Ukraine, this [election] is a decisive choice," he continued, adding that a vote for Zelenskiy could mean "the return of Ukraine back to the influence of the Russian Empire."
Outside the Maritime Academy where Zelenskiy cast his vote, Kateryna Chala, the founder of an IT company who was joined by her three children, told RFE/RL in English that she had voted for Poroshenko.
At the same time, Chala admitted that Poroshenko had made mistakes during his presidency, but said he had ultimately put Ukraine on a Westward path she hopes will eventually lead to membership in the EU and NATO.
"We have a lot of problems...like the high price for gas, [high] prices in our shops...I understand it's not possible to create a miracle and fix everything in just one day," she said.
Zelenskiy won the first round of the election on March 31, picking up 30 percent. Poroshenko polled 16 percent to come in second.
Zelenskiy has said he supports Ukraine's eventual membership in NATO but only if it is approved by a referendum. He has insisted that Russia must return the Black Sea region of Crimea, which Moscow annexed in 2014, and pay reparations.
He has called for direct talks with Russia over the conflict in eastern Ukraine. In the past, Moscow has rejected such proposals, claiming the conflict – which has claimed more than 13,000 lives -- is an internal matter for Ukraine and urging Kyiv to negotiate with representatives of the Moscow-backed separatist formations.
The International Criminal Court (ICC) ruled in November 2016 that the war in eastern Ukraine is "an international armed conflict between Ukraine and the Russian Federation."
At a Kyiv campaign rally on April 18, Poroshenko warned the country it would be "very risky to experiment with the post of president and commander in chief" at this time. He asked voters to give him a second five-year term.
"I once again ask you to forgive me," Poroshenko said. "What did not work out is what hurts the most."
Incumbent President Petro Poroshenko speaks to RFE/RL as he arrives at Kyiv's House of Officers to cast his ballot with his wife, Maryna Poroshenko, on April 21.
Poroshenko's supporters give him credit for strengthening the depleted military that he inherited from pro-Russian President Viktor Yanukovych, who fled the country in 2014 amid massive protests.
He also signed an Association Agreement with the European Union and secured visa-free travel for Ukrainians to the EU. He also pushed successfully for Ecumenical Patriarch Bartholomew of Constantinople to recognize the Orthodox Church of Ukraine as independent of the Moscow Patriarchate.