South Korea’s main opposition party leader Lee Jae-myung was stabbed in the neck during a visit to the southern city of Busan on Tuesday in an assault that left him bloodied but conscious, party officials said.

Lee was touring the construction site of the Gadeokdo New Airport and talking to reporters when he was attacked, leaving the politician with a 1-centimeter laceration on the left side of his neck, Democratic Party spokesperson Kwon Chil-seung said.

Lee suffered “suspected damage to his jugular vein” and doctors were concerned he may have additional bleeding, Kwon said, citing doctors.

“He will quickly undergo a surgery” at the Seoul National University Hospital, after having been transferred there from Busan, the spokesperson said, describing the attempt on Lee’s life an act of “terrorism” and “a serious threat to democracy.”.

Earlier in the day Democratic Party’s floor leader Hong Ik-pyo said Lee was “in a conscious state” in hospital.

Footage of the brazen attack, captured on live television at the press conference, showed an unidentified man at the front of the crowd suddenly jumped at Lee and struck him in the neck, sending Lee collapsing backwards.

The attacker was then wrestled to the ground and restrained by several people.

Photos showed Lee lying on the floor with his eyes shut and a handkerchief pressed against his neck. Small amounts of blood were visible in some of the photos.

South Korea’s President Yoon Suk Yeol expressed “deep concern” for Lee’s safety after the attack, according to the presidential office.

Yoon emphasized such violence “should not be tolerated under any circumstances” and ordered the police to swiftly investigate, the office said.

Democratic Party floor leader Hong called for party members to remain calm and refrain from making political interpretations of the incident.

South Korea’s politics have been riven by deep polarization, particularly in recent years which saw former President Park Geun-hye jailed on abuse of power and bribery charges before being pardoned and released in 2021.

Lee, 59, a liberal former provincial governor, narrowly lost to Yoon of the conservative People Power Party in the presidential election in March 2022.

Lee became the leader of the Democratic Party five months later and has been gearing up his party for the parliamentary elections in April.

South Korea has witnessed high-profile incidents of political violence in the past.