South Korean police started on Tuesday providing additional security for the leader of the main opposition Democratic Party, after lawmakers had warned of a potential assassination plot targeting Lee Jae-myung, the Yonhap News Agency reported. The move comes after the party had last week urged police to ramp up security for Lee after some of its lawmakers said they were tipped off about an assassination plot against him. Tensions have been running high in South Korea since President Yoon Suk Yeol briefly imposed martial law last December, triggering the country's worst political crisis in decades.