The assailant, center, in the Jan. 2, knife attack on opposition leader Lee Jae-myung is taken to the prosecution after leaving a police station in the southeastern city of Busan in this Jan. 10 photo. Newsis

An appellate court on Wednesday upheld a 15-year prison sentence for the assailant in a knife attack on opposition leader Lee Jae-myung early this year.

The assailant, a 67-year-old man surnamed Kim, was sentenced to 15 years in prison in July for stabbing Lee in the neck during the opposition leader's visit to the southeastern city of Busan on Jan. 2.

The Busan High Court rejected Kim's appeal and upheld the ruling, saying the sentence was "fully acceptable" given the assailant tried to justify his crime and concealed evidence.

The court also said responsibility for the crime was "heavy" considering he tried to disrupt free and fair elections by carrying out the attack ahead of parliamentary elections.

Kim was charged with attempted murder and violating election laws.

Lee, the leader of the main opposition Democratic Party of Korea, was hospitalized for eight days after the attack. (Yonhap)