Lee Jae-myung, leader of South Korea's main opposition party, is recovering from surgery after being stabbed in the neck during a visit to the southern city of Busan on Tuesday.

As Lee was speaking to a crowd of supporters and reporters, the suspect, wearing a paper crown with Lee's name on it, approached and asked for an autograph.

He then moved forward and attacked him, with an 18 cm (7 in) long knife purchased online, police said at a briefing.

According to Busan police, the attacker, who was arrested at the scene, is a man in his sixties.

Son Jae-han, a Busan police officer, told a news briefing that the attacker was born in 1957. They did not identify the suspect and said the motive was under investigation.

Democratic Party spokesman Kwon Chil-seung said Lee underwent vein reconstruction surgery and is recovering in the intensive care unit.

Kwon earlier said in a statement that Lee Gaedokdo was visiting the construction site of the new airport and talking to reporters when he was attacked,

Due to this the politician suffered a 1-centimeter wound on the left side of his neck.

According to the presidential office, South Korean President Yoon Suk Yeol expressed "deep concern" for Lee's safety following the attack.