Liberal Lee Jae-myung projected to win South Korea election overshadowed by martial law crisis

South Korea's liberal party candidate Lee Jae-myung is projected to win the country's snap presidential election, according to projections by the country's broadcasters on Tuesday.

Reuters has not independently confirmed the results of the joint exit poll by broadcasters KBS, MBC and SBS, which put Lee on 51.7% and his conservative rival Kim Moon-soo on 39.3%.

The exit poll has in previous elections mostly been in line with the final results. A separate poll by broadcaster JTBC put Lee on 50.6% and Kim on 39.4%. Channel A also predicted a Lee win by similar margins.

Around 78% of South Korea's 44.39 million eligible voters had cast ballots to pick the leader of Asia's fourth-largest economy, hoping to draw to a close six months of turmoil triggered by a shock martial law briefly imposed by former leader Yoon Suk Yeol.

After being impeached by parliament in December, Yoon was removed from office by the Constitutional Court on April 4, less than three years into his five-year term, triggering the snap election that now stands to remake South Korea's political leadership and foreign policies.

Lee had called the election "judgment day" against the previous Yoon administration and the conservative People Power Party, accusing them of having condoned the martial law attempt by not fighting harder to thwart it and even trying to save Yoon's presidency.

The winner must tackle challenges including a society deeply scarred by divisions made more obvious since the attempt at military rule, and an export-heavy economy reeling from unpredictable protectionist moves by the United States, a major trading partner and a security ally.

If the exit poll's projection is accurate, Lee should be on course to officially become president when the National Election Commission declares the winner sometime on Wednesday, immediately taking power including becoming commander-in-chief of the military.