State prosecutors summoned a secretary to President Moon Jae-in on Wednesday over the allegations that Cheong Wa Dae is involved in an Ulsan mayor election scandal.

Lee Gwang-cheol, secretary for civil affairs, appeared at the Seoul Central District Prosecutors Office to face questioning over suspicions that he had played a secret role behind the 2017 police probe into alleged corruption by Kim Ki-hyun, the mayor of Ulsan.

Kim, a member of the main opposition Liberty Korea Party, was seeking reelection. Song Cheol-ho, a longtime friend of Moon, was the flag bearer of the ruling Democratic Party, and he finally won the local election.

Kim argued that he had faced an unjust police probe in Cheong Wa Dae's campaign to help Song in the poll.

Lee, who was a deputy secretary for civil affairs at that time, has flatly denied suspicions involving him and stressed that many related news reports are untrue.

The prosecution also plans to interrogate Im Jong-seok, who served as the Cheong Wa Dae chief of staff in 2017.

Im wrote on his Facebook account that he would appear at the prosecutors' office for questioning Thursday.

He's accused of having forced a DP official to give up his bid for the Ulsan mayorship so that Song can run in the election.

Im strongly criticized the prosecution for what he claimed was a politically motivated investigation into the case.

He described it as an "abuse of the prosecution's power" by Prosecutor General Yoon Seok-youl for political gains amid the Moon administration's prosecution reform drive. (Yonhap)