The vice chairman of South Korea's biggest business lobby was summoned Friday over its involvement in raising funds for two nonprofit foundations allegedly linked to a controversial figure with close ties to President Park Geun-hye.

Lee Seung-cheol, vice chief of the Federation of Korean Industries (FKI), appeared before the Seoul Central District Prosecutors' Office in southern Seoul, to undergo questioning over the Mir Foundation and the K-Sports Foundation.

The lobby, which has large companies as Samsung and Hyundai as its members, is said to have spearheaded the collection of around 80 billion won ($70 million) from conglomerates for the two foundations. Lee is suspected of having played a role in the process.

There have been allegations that the money at the foundations -- established in 2015 and early this year, respectively -- was funneled to Choi Soon-sil, who is at the center of a political scandal that is rocking the country.

"I will fully cooperate with the investigation," Lee told reporters before entering the prosecutors' office. He declined to comment on the allegations raised.

The summons came a day after the prosecution expanded its investigation team to look into a string of corruption allegations surrounding Choi, who is suspected to have peddled influence based on her connection with President Park Geun-hye.

On Tuesday, Park offered a rare public apology over a leak of dozens of presidential speeches to Choi before they were made public. Acknowledging her ties to Choi, which go back decades, the president said she asked for consultation "out of the best intentions" to be more thorough in her work.

Still, the scandal has only been snow-balling as local media outlets have been reporting that Choi might have intervened in other state affairs.

Choi -- the daughter of Park's late mentor Choi Tae-min and ex-wife of Park's former secretary Chung Yun-hoi -- does not have a government position.

In a recent interview with a local daily, Choi flatly denied any allegations raised against her, except that she received and edited drafts of the president's speeches. She is currently known to be in Germany.

Prosecutors here have been summoning a number of officials from the government and private companies related to the scandal, including Ko Young-tae, one of the closest figures to Choi.

Ko, a former member of the national fencing team during the 1998 Asian Games in Bangkok who now heads a fashion company, returned to South Korea from Bangkok on Thursday and volunteered to appear at the prosecutors' office later in the day. (Yonhap)