South Korea's new president Lee Jae-myung vows economic revival, judgment on martial law

South Korea woke on Wednesday to a new liberal president, Lee Jae-myung, who vowed to raise the country from the turmoil of a martial law crisis and revive an economy reeling from slowing growth and the threat of global protectionism.

Lee's decisive victory in Tuesday's snap election stands to usher in a sea change in Asia's fourth-largest economy, after backlash against a botched attempt at military rule brought down Yoon Suk Yeol just three years into his troubled presidency.

With 100 percent of the ballots counted, Lee had won 49.42 percent of the nearly 35 million votes cast while conservative rival Kim Moon-soo had taken 41.15 percent in the polls that brought the highest turnout for a presidential election since 1997, according to National Election Commission data.

The 61-year-old former human rights lawyer called Tuesday's election "judgment day" against Yoon's martial law and his People Power Party's failure to stop the ill-fated move.

"The first mission is to decisively overcome insurrection and to ensure there will never be another military coup with guns and swords turned against the people," Lee said in a victory speech outside parliament.

"We can overcome this temporary difficulty with the combined strength of our people, who have great capabilities," he said.

Lee was officially confirmed as president by the National Election Commission on Wednesday and immediately assumed the powers of the presidency and commander in chief.

An abbreviated inauguration is planned at parliament at 11am (2am GMT), an Interior Ministry official said.

A daunting slate of economic and social challenges await the new leader, including a society deeply scarred by divisions following the martial law attempt and an export-heavy economy reeling from unpredictable protectionist moves by the United States, a major trading partner and a security ally.

The government under a caretaker acting president had made little progress in trying to assuage crushing tariffs announced by US President Donald Trump's administration that would hit some of the country's major industries, including autos and steel.

"President Lee will find himself with little to no time to spare before tackling the most important task of his early presidency: reaching a deal with Trump," the Washington-based Center for Strategic and International Studies said in an analysis.