In South Korea, an exit poll showed on Tuesday that former human rights lawyer Moon Jae-in had won the presidential election by a landslide.
The Democratic Party's contender had 41.4 percent support, according to the joint survey by three television stations. Conservative Hong Joon-pyo was far behind on 23.3 percent. Centrist Ahn Cheol-soo was third on 21.8.
"I will be president for all South Koreans," Moon told cheering supporters on Gwanghwamun Square in Seoul.
South Koreans voted in a snap presidential election to choose a successor to Park Geun-hye, who was ousted from power over a huge corruption scandal in March.
More than 139,000 polling stations opened across the country at 6 a.m. local time (2100 GMT) on Tuesday. Voting is scheduled to close at 8 p.m. (1100 GMT).
The turnout is expected to hit a record high as many voters are angered by the corruption scandal, which rattled both the government and business elite amid the country’s slowing growth and high unemployment rate.
The vote will end a months-long leadership vacuum in the country. Ousted Park, 65, is accused of colluding with her friend, Choi Soon-sil, to pressure big businesses, including Samsung, to contribute huge sums to non-profit foundations that were set up to back up her initiatives.
On March 10, the Constitutional Court ruled to remove Park from office after she was impeached in December 2016.
Later that month, she was jailed over the charges and was officially indicted in April. She has apologized for putting trust in her imprisoned friend, but has denied that she ever broke the law.
On May 4, hundreds of thousands of South Koreans cast their ballots in early voting.
The final Gallup Korea survey before a week-long pre-election blackout gave him 38 percent support, with former tech mogul Ahn Cheol-soo lagging behind with 20 percent.
“I feel the people’s strong will to change the government... We can make it a reality only when we vote,” Moon said after casting his ballot at a voting station in western Seoul.
The election comes amid increased tensions with North Korea over its nuclear and missile programs.
Moon was a former presidential Chief of Staff. In 2012, he ran against, and narrowly lost to, former President Park.
Moon has said he could talk with North Korean leader Kim Jong-un. A former Special Forces soldier, Moon wants good relations with Pyongyang as well as Washington. Experts say he also seeks to build up the defenses so his government will not have to rely on the United States if confronted by the North.
Hong Joon-pyo, of Park’s Liberty Korea Party, who came third with 16 percent, called on voters to back him, branding Moon “a pro-Pyongyang leftist.”