SEOUL - South Korea's main opposition Democratic Party of Korea on Sunday named Lee Jae-myung, the party's ex-leader, as its candidate for the snap presidential election slated for June 3.

Lee has been leading opinion polls for weeks with a double-digit gap over contestants from the conservative People Power Party, which will name its candidate on May 3.

"From this point on, Lee Jae-myung is not only the candidate of the Democratic Party, but also the candidate of all the people yearning for the end of insurrection, an overcoming of the crisis, for those who seek unity and happiness," Lee said in an acceptance speech after winning his party's candidacy.

Lee said he would strengthen South Korea's defense capabilities and work to make the country a leader in high-tech industries, a cultural powerhouse and an exemplary democracy.

Lee led the Democratic Party to a landslide victory in a parliamentary election in 2024 and had been widely expected to win the primary election, after he easily defeated two other candidates from his party in regional primaries.

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The 61-year-old lawyer-turned-politician lost the last presidential election in 2022 by the slimmest margin in South Korea's democratic history.

That election was won by Yoon Suk-yeol, who was impeached by the Constitutional Court earlier this month over his short-lived imposition of martial law.

In a separate speech earlier on Sunday, Lee compared Yoon's attempt to impose martial law to abuses by earlier authoritarian leaders, promising to guide the country out of its political and economic crisis.

Lee was among the lawmakers who rushed to the National Assembly on the night of Yoon's December 3 martial law declaration to ensure parliament voted down the military order.

Last year, Lee survived a knife attack in the southern city of Busan while touring the site of a proposed new airport and speaking to journalists and supporters.

Lee, who became the party's leader in 2022 and stepped down earlier this month to run for the presidency, is no stranger to controversy.

Earlier this year an appeals court threw out his guilty verdict on charges of violating the election law earlier, though the Supreme Court is deliberating on the case for a final ruling.

He also faces several trials on matters ranging from bribery to charges mostly linked to a $1 billion property development scandal.

READ MORE: Yonhap: S. Korea indicts opp leader Lee over property graft

Before becoming the leader of the Democratic Party, Lee also served as mayor of Seongnam and governor of Gyeonggi province, the most populous in the country.