People watch a TV screen showing former South Korea's main opposition Democratic Party leader Lee Jae-myung announces his presidential bid via a video message at the Seoul Railway Station in Seoul, South Korea, Thursday, April 10, 2025. (AP Photo/Ahn Young-joon)

SEOUL, South Korea (AP) — South Korean opposition leader Lee Jae-myung, widely seen as the frontrunner in a presidential by-election triggered by the removal of President Yoon Suk Yeol last week, officially announced a presidential bid on Thursday, vowing to heal a starkly divided nation through economic growth.

Lee, who narrowly lost the 2022 election to Yoon, led the liberal Democratic Party's campaign to oust the former president over his December declaration of martial law.

Lee recently stepped down as the party's chairman to focus on campaigning for the June 3 election. He is considered the clear frontrunner in party's primary. Kim Dong-yeon, the Democratic governor of Gyeonggi province and a longtime financial policymaker, also told reporters Wednesday that he intends to run for president.

Yoon's downfall has left the conservative People Power Party in disarray, with roughly 10 politicians expected to seek the nomination, reflecting a split between Yoon loyalists, who still control the party's leadership, and reformists calling for a fresh start.

In a video message, Lee said that Yoon's martial law saga exposed the country's deep divisions and social conflicts, and argued that the root cause was a widening rich-poor gap. He promised aggressive government spending to jolt economic growth and ease income polarization.

"We have more than we did in the past, but wealth is too concentrated in certain areas," Lee said. "With economic growth rates declining worldwide, it has become difficult to maintain and develop an economy solely on the strength of the private sector. However, with government-led talent development and extensive investments in technological research and development, we can revive the economy."

Lee said it was crucial to maintain a robust alliance with the United States and to pursue three-way cooperation with Japan, but he stressed that South Korea's national interest should come first in "every decision."

Lee, who has served as a lawmaker, provincial governor and city mayor, is adored by supporters for his outspoken style and has long positioned himself as an anti-elitist. His critics view him as a populist who stokes division and demonizes conservative opponents while failing to offer realistic funding plans to achieve his ambitious goals.

Kweon Seong-dong, floor leader of the People Power Party and a staunch Yoon loyalist, said that if Lee becomes president, he will "ruthlessly wield the sword of dogmatism and retribution" and further deepen the country's divisions.

Lee also has his own set of legal troubles, facing five different trials for corruption and other criminal charges.

Earlier this month, the Constitutional Court upheld Yoon's impeachment by the legislature and formally removed him from office over the martial law decree, triggering a presidential by-election within 60 days. The next president will serve a full 5-year term.

Former PPP leader Han Dong-hoon, who heads the party's anti-Yoon faction, was expected to announce his presidential bid on Thursday. Among the conservatives' presidential hopefuls, former Labor Minister Kim Moon Soo is considered to be the most pro-Yoon.

Kim, Daegu Mayor Hong Joon-pyo and senior PPP lawmaker Ahn Cheol-soo — a former computer software entrepreneur and three-time presidential candidate — have declared their intentions to run for president. Seoul Mayor Oh Se-hoon is expected to enter the race later.