South Korea's Supreme Court said it will rule on Thursday in a criminal case that could determine whether the frontrunner for the June 3 snap election, former opposition party leader Lee Jae-myung, can run for president.

During Yoon's six hours of martial law on December 3, Lee climbed the National Assembly's walls to avoid security cordons deployed on Yoon's orders. He livestreamed his exploit, urging viewers to come to parliament and demonstrate to prevent the arrest of lawmakers.

South Korea’s main liberal opposition party has tapped its former leader Lee Jae-myung as presidential candidate in the June 3 vote.