South Korea's opposition Democratic Party leader Lee Jae-myung was stabbed in the neck during a visit to the southern port city of Busan on Tuesday, the Yonhap news agency reported.

Lee was attacked by an unidentified man while touring the site of a proposed airport, Yonhap said.

The assailant appeared to be a man in his 50s or 60s. He approached Lee asking for an autograph, then suddenly lunged forward and attack him, news reports said. The assailant was quickly subdued and arrested at the scene, Yonhap said.

Video clips on YTN television and another posted on X showed the attack, with a man lunging at Lee with his arm stretched out. Lee grimaced and collapsed to the ground.

News photographs showed Lee lying on the ground with his eyes closed and other people pressing a handkerchief against the side of his neck.

Lee has been transported to a hospital, Yonhap said.

Although there are strict restrictions on gun possession, South Korea has a history of political violence involving other types of weapons.

Then conservative opposition party leader Park Geun-hye, who later served as president, was attacked at an event in 2006 with a knife and suffered a gash on her faced that required surgery.