Main opposition party leader Lee Jae-myung was attacked by an assailant and stabbed in the neck by a knife during his tour to Busan on Tuesday morning.

Lee was stabbed around 10:27 a.m. after talking to reporters during a visit to the site of a new airport off the coast of Busan. The assailant was detained by police at the scene.

Lee sustained a cut 1 centimeter wide and was conscious when the paramedics arrived at the scene, emergency authorities said, adding that his injuries were not thought to be life threatening.

The main opposition leader was rushed to Pusan National University Hospital in southern Busan by helicopter some 20 minutes after the stabbing. After receiving emergency treatment in Busan, he was airlifted to Seoul National University Hospital around 1 p.m. for surgery.

Lee sustained an injury to his jugular vein, which put him at risk of additional bleeding and possible hemorrhage, according to the Democratic Party of Korea.

Police has decided to charge the 67-year-old assailant surnamed Kim with attempted murder. During questioning, Kim confessed he had "attempted to murder" Lee, according to Busan Metropolitan Police.

Kim had walked through a crowd of reporters and asked Lee for an autograph. He then pulled out an 18-cm-long knife to stab the opposition leader's neck. The weapon was purchased online, the police explained.

Kim was wearing a blue paper crown decorated with the words “I’m Lee Jae-myung” in Korean, paired with a headband worn by Lee’s hardcore supporters, a video streamed on YouTube by one of Lee's followers showed.

President Yoon Suk Yeol expressed deep concern on the matter saying that “such acts of violence should not be condoned in our society.” He ordered authorities to swiftly investigate the case and offer proper medical attention for Lee.

Both the prosecution and the police announced plans to establish a special response team to investigate the incident.

National police chief Yoon Hee-keun vowed to strengthen the protection of public figures.

The Democratic Party soon released a statement calling the attack against its leader an “attack against democracy.”

“It’s an act of terror against our leader Lee Jae-myung and a dire threat against democracy,” the party’s senior spokesperson Rep. Kwon Chil-seung said in a statement.

The ruling People Power Party Interim Chairman Han Dong-hoon echoed Yoon, saying that such attacks should have never happened and wished Lee a swift recovery.

Lee Nak-yon, an ex-Democratic Party leader and former prime minister, said he was “shocked and enraged” by the incident.

The attack comes 99 days ahead of the April general elections. Lee initially planned to attend a luncheon with former President Moon Jae-in after visiting Busan.

There have been similar knife attacks on politicians and diplomats in Korea.

Former President Park Geun-hye was injured in a knife attack in 2006 when she was the leader of the conservative Grand National Party, a predecessor of the current People Power Party. It left an 11-cm cut from her ear to her lower chin. She was campaigning for her party’s Seoul city mayoral candidate, Oh Se-hoon, at the time.

In 2015, the then-US ambassador to South Korea, Mark Lippert, was slashed in the face with a razor by a 55-year-old political extremist named Kim Ki-jong during a function in Seoul. Lippert took 80 stitches to his face and hand. Lippert's assailant was sentenced to 12 years in prison.