Seoul, Jun 3 (AP) South Korea's liberal opposition candidate Lee Jae-myung was poised to win an early presidential election, vote counts and media projections suggested, while his challenger conceded defeat early Wednesday.

The victory would cap months of political turmoil triggered by the stunning but brief imposition of martial law by now-ousted conservative leader Yoon Suk Yeol.

Even before Lee's win was formally declared, his main conservative rival, Kim Moon Soo, conceded, telling journalists he "humbly accepts the people's choice” and congratulated Lee for winning the election.

It was unclear whether Lee's election would cause any major, immediate shift in South Korea's foreign policy. Lee, previously accused by critics of tilting toward China and North Korea and away from the US and Japan, has repeatedly stressed South Korea's alliance with the US as the foundation of its foreign policy.

The toughest external challenges awaiting a new president are US President Donald Trump's tariff policy and North Korea's advancing nuclear programme. But experts say whoever becomes president in South Korea can't do much to secure major progress in South Korea's favour on those issues.

With more than 86 per cent of ballots counted as of 1:45 am Wednesday, Lee, the Democratic Party candidate, led with more than 48 per cent of votes and Kim had 42.7 per cent.

The exit poll by South Korea's three major television stations — KBS, MBC and SBS — earlier showed Lee projected to obtain 51.7 per cent of total votes cast, beating Kim with 39.3 per cent.

Preelection surveys suggested Lee appeared headed for an easy win, riding on deep public frustration over the conservatives in the wake of Yoon's martial law debacle that plunged South Korea into political turmoil.

“With the vote counting still underway, it's premature to say anything definitively, but if the results stand as they are now, I pay my respects to the great decision of our people,” Lee said outside his apartment in Incheon, just west of Seoul, as his supporters shouted his name.

Hundreds of Lee supporters gathered outside the National Assembly in Seoul, waving Korean flags and singing.

Nearly 80 per cent of the country's 44.4 million eligible voters cast ballots, according to an interim tally. That's one of the highest turnouts for a presidential election in South Korea, reflecting public eagerness to move past the political turmoil.

The winning candidate will immediately be sworn in as president Wednesday for a single, full term of five years without the typical two-month transition period.

Pragmatic diplomacy Lee, who served as governor of Gyeonggi province and mayor of Seongnam city, has been a highly divisive figure in politics for years.

As a former child laborer known for his inspirational rags-to-riches story, Lee came to fame through biting criticism of the country's conservative establishment and calls to build a more assertive South Korea in foreign policy. That rhetoric has given him an image as someone who can institute sweeping reforms and fix the country's deep-seated economic inequality and corruption.

His critics view him as a dangerous populist who relies on political division and backpedals on promises too easily.

On foreign policy, Lee has has steadfastly vowed to pursue pragmatic diplomacy. He has promised to solidify a trilateral Seoul-Washington-Tokyo partnership, a stance that isn't much different from the position held by South Korea's conservatives.

He said he would pursue better ties with North Korea but acknowledged that it would be “very difficult” to realize a summit with North Korean leader Kim Jong Un anytime soon. This signals Lee won't likely initiate any drastic steps meant to improve relations with North Korea.

Experts say there aren't many diplomatic options for South Korea as it tries to address Trump's tariff hikes and calls for South Korea to pay more for the cost of the US military presence, as well as North Korea's headlong pursuit of nuclear weapons. Experts say that has made both Lee and Kim Moon Soo avoid unveiling ambitious foreign policy goals.

Paik Wooyeal, a professor at Seoul's Yonsei University, said foreign policy strategists for Lee understand there isn't much South Korea can do to bring about a denuclearization of North Korea. Paik said Lee also doesn't share the Korean nationalistic zeal held by ex-liberal President Moon Jae-in, who met Kim Jong Un three times during his 2017-22 term.

Impact of tariff hikes Lee's government still could become engaged in “a little bit of friction” with the Trump administration, while a Kim Moon Soo government, which prioritises relations with Washington, would likely offer more concessions to the US, said Chung Jin-young, a former dean of the Graduate School of Pan-Pacific International Studies at South Korea's Kyung Hee University.

Chung predicted Lee won't be able to pursue overly drastic steps on foreign policy and security, given the country's foreign exchange and financial markets are vulnerable to such changes.

Lee has preached patience over Trump's tariff policy, arguing it would be a mistake to rush negotiations in pursuit of an early agreement with Washington. Kim Moon Soo has said he would meet with Trump as soon as possible.

On Monday, South Korean trade officials held an emergency meeting to discuss a response to Trump's announcement that the US will raise tariffs on steel and aluminum products to 50 per cent beginning Wednesday.

South Korea's central bank last week sharply lowered its 2025 growth outlook to 0.8 per cent, citing the potential impact of Trump's tariff hikes and weak domestic demand worsened by the political turmoil of past months.

Healing domestic divide The election serves as another defining moment in the country's resilient democracy, but observers worry a domestic divide worsened after Yoon's martial law stunt is far from over and could pose a big political burden on the new president.

The past six months saw large crowds of people rallying in the streets to either denounce or support Yoon, while a leadership vacuum caused by Yoon's impeachment and ensuing formal dismissal rattled the country's high-level diplomatic activities and financial markets.

Lee has promised to heal the national split, but his vow to thoroughly hold those involved in Yoon's martial law stunt accountable has sparked concerns that he would use investigations to launch political retaliations against his opponents.

In a Facebook posting earlier Tuesday, Lee called for voters to “deliver a stern and resolute judgement” against the conservatives over martial law. In a campaign speech Monday, Lee claimed that a win by Kim Moon Soo would mean the “return of the rebellion forces, the destruction of democracy and the deprival of people's human rights.” Kim, a former labour minister under Yoon, said that a Lee win would allow him to wield excessive power.

Lee “is now trying to seize all power in South Korea,” Kim told one rally. (AP) GSP