A ruling party lawmaker and former aide to President Moon Jae-in was questioned by police on Friday over alleged involvement in the manipulation of online news comments led by a power blogger.

Rep. Kim Kyoung-soo of the Democratic Party appeared at the Seoul Metropolitan Police Agency at around 10 a.m., two days after police formally subpoenaed him.

"I will explain myself fully, with confidence and without a single doubt," he told reporters.

Police are to question him as a witness in the probe into allegations that the blogger, better known by his nickname "Druking," mobilized a team in January to jack up the number of clicks in support of comments critical of the Moon government on Internet news articles.

The scandal has emerged ahead of the June local elections, providing fodder for the struggling main opposition Liberty Korea Party's attacks on the ruling party. The LKP is pushing for an independent probe into the case.

Kim, known for his close ties with the president, is running for governor in South Gyeongsang Province.

Police said they will focus on finding out how much he was involved in and whether he had knowledge of the alleged comment rigging. Police are also looking into whether he knew about the 5 million won ($4,600) that one of his aides received from Druking's associate early this year, which was returned after Druking was arrested.

Kim will also be interrogated over allegations that Druking requested Kim recommend his acquaintances as consul general in Osaka, Japan, and as a presidential official.

Druking has told police that the comment rigging was carried out in response to the refusal of his request. He has admitted to using a software program for the scheme.(Yonhap)