Video shows the moment South Korean opposition leader Lee Jae-myung was stabbed in neck

South Korean media cited witnesses as saying the man used a knife-like weapon to injure Lee Jae-myung's neck.

Shortly after South Korean opposition party leader Lee Jae-myung was attacked and injured during a visit to the southeastern city of Busan on Tuesday, several disturbing videos have surfaced online purportedly showing an unidentified man stabbing him in his neck.

South Korean opposition party leader Lee Jae-myung is attended to after being attacked in Busan on January 2. (AFP)

Busan’s emergency office said Lee Jae-myung was attacked as he visited the construction site of a new airport in the city. It said 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 Lee’s neck.

In one of the videos, Lee is captured addressing the media when the assailant stabbed the leader from the front. Following this, Lee falls on the ground, while security personnel pin down the attacker.

Note: The content of this video is disturbing, viewer discretion is advised.

South Korean President Yoon Suk Yeol condemned the attack and said it was unacceptable, the Yonhap news agency reported.

Emergency responders were seen carrying Lee into an ambulance. He was later taken to hospital on a helicopter, according to the Yonhap news agency. The agency said he was bleeding but conscious as he was transported to the Pusan National University Hospital.

"This is an act of terror against Lee and a serious threat to democracy that should never occur under any circumstances," Kwon Chil-seung, an MP from Lee's Democratic Party, told reporters outside the hospital.

"As to Lee's condition, we are waiting for the medical staff's assessment," he added, demanding a "thorough" police investigation into the attack.

Police in Busan said Lee suffered a "one-centimetre laceration on his neck" and that he "remains conscious and bleeding is minor", according to South Korean news outlet Chosun Ilbo.

Who is Lee Jae-myung?

• Lee Jae-myung lost the 2022 presidential election to Yoon Suk Yeol by a narrow margin. Lee, a liberal former provincial governor, is known as an outspoken leader. His supporters see him as an anti-elitist hero who could reform establishment politics, eradicate corruption and solve growing economic inequality.
• Critics view Lee as a dangerous populist who relies on stoking divisions and demonising his conservative opponents, news agency AP reported.
• A former child factory worker who suffered an industrial accident as a teenage school drop-out, Lee rose to political stardom partly by playing up his rags-to-riches tale.
• He is widely expected to run for president again in 2027, and recent polls have indicated that he remains a strong contender.
• But Lee's bid for the top office has been overshadowed by a string of scandals.
• He avoided arrest in September when a court dismissed a request from the prosecution for him to be taken into custody pending trial on various corruption charges.
• Lee still faces trial on charges of bribery in connection with a firm that is suspected of illicitly transferring $8 million to North Korea.
• He is also accused of breaching his duties, allegedly resulting in a loss of 20 billion won ($15 million) for a company owned by Seongnam city during his term as its mayor. Lee has denied all allegations against him.
• In August last year, he launched a hunger strike against what he called the Yoon government's "incompetent and violent" policies.
• He was hospitalised because of fasting-related ailments on September 18 after not eating for 19 days.

(With inputs from agencies)