South Korea's former Prime Minister Lee Wan-koo filed an appeal against a court ruling that gave him an eight-month jail term last week for bribery, legal sources said Thursday.

Lee, who was convicted of taking 30 million won from Sung Wan-jong, the late chairman of construction firm Keangnam Enterprises Inc., at his election office in April 2013 brought the case to the Seoul High Court.

Last week, the Seoul Central District Court handed down a jail term suspended for two years and ordered him to forfeit 30 million won.

Right after the ruling was delivered, Lee, who stepped down in April under mounting suspicion, said he will prove his innocence and will not run for the upcoming general election in April.

The corruption scandal flared up after Sung left a note and a recorded interview claiming that he gave money to eight politicians, including Lee and Hong Joon-pyo, governor of South Gyeongsang Province, as well as President Park Geun-hye's former and current chiefs of staff.

Prosecutors indicted Lee and Hong in July 2015 while not prosecuting the others, citing a lack of evidence and the statute of limitations.

Sung hanged himself on April 9 just hours before a court hearing that would have determined the legality of his arrest regarding his embezzlement charges. (Yonhap)