South Korean opposition leader Lee Jae-myung was attacked and injured by an unidentified man during a visit to the south-eastern city of Busan, officials said.
Busan’s emergency office said Mr Lee was attacked on Tuesday as he visited the construction site of a new airport in the city.
It said Mr Lee, head of the main opposition Democratic Party, was conscious but his exact condition was unknown.
South Korean media cited witnesses as saying the man used a knife-like weapon to injure Mr Lee’s neck.
TV video showed Mr Lee lying on the ground with a person pressing a handkerchief to his neck to stop the bleeding.
The reports said police arrested the attacker on the spot. They said the man was wearing something that looked like a crown on his head.
Mr Lee lost the 2022 presidential election to Yoon Suk Yeol by a narrow margin.
