A South Korean court on Thursday issued an arrest warrant for the suspect wanted for the attack on Lee Jae-myung, chairman of the main opposition Democratic Party, Yonhap reported. 

The suspect, identified only by his surname Kim, 67, stabbed Lee in the neck while posing as an autograph-seeker on Tuesday morning during Lee's visit to the southeastern city of Busan, according to a Yonhap report.

Kim reportedly had a history of extreme political views and was immediately detained at the scene.

The suspect's motive isn't known, though he told police that he attempted to kill the politician and that he had plotted the attack alone.

Police officers searched the suspect's residence and office in the central city of Asan and examined his cellphone on Wednesday.

Lee was out of intensive care and was recovering from surgery to repair a major vein that was sliced in Tuesday's attack, a surgeon who operated on him said on Thursday.

The opposition leader requires continued observation as the injury to the jugular vein he suffered required difficult procedures to repair, and post-surgery complications could not be ruled out, Professor Min Seung-kee from Seoul National University Hospital's vascular surgery unit told a news briefing.

"(Lee) is fortunately recovering well," added Min.

The attack shocked the country and was condemned by his party and his rivals alike. It renewed questions about the safety of high-profile politicians considering the country's history of political violence despite strict gun controls.

"The act of terror against Chairman Lee Jae-myung was clearly a challenge against democracy and a threat against democracy," Democratic Party floor leader Hong Ik-pyo said at a party leadership council meeting.

He also urged a speedy investigation and tougher security for high-profile political figures.

Jin Jeong-hwa, a party supporter who was a witness at the scene of the stabbing, said the incident clearly showed the need for stronger and professional security protection for political leaders, not simply police who are deployed to monitor.

"People like opposition leaders really need a dedicated security detail," Jin said, adding that it was clear from his experience at political events that Lee was very much exposed to personal safety threats.

(With input from agencies)