South Korean President Park Geun-hye had a major role in the influence peddling scandal that engulfed her administration, prosecutors claimed on Sunday (20 November) as they charged the president's longtime friend Choi Soon-sil and two former aides.

Chief prosecutor Lee Young-ryeol said Park was "involved as a co-conspirator" but was immune from prosecution. "The president played a collusive role in a considerable portion of the criminal activities involving the (three) people," Lee added.

"Based on our investigations into the case, we judge President Park, to a significant extent, had an accomplice role in the crime. We can't indict [Ms Park] because of her constitutional right, but we'll continue to investigate her," the Wall Street Journal quoted him as saying. Under South Korean law, the president is immune from prosecution while in office.

Choi Soon-sil was charged with interfering in state affairs and forcing corporations into giving millions of dollars to foundations controlled by her. Two ex-presidential aides, An Chong-bum and Jeong Ho-Seong, were also indicted on charges of collaborating with Choi.

Earlier this month, Choi and one of the aides were arrested on charges of abuse of power, coercion and fraud. Another aide was arrested for allegedly leaking confidential state documents. Park is facing accusations of helping Choi to get money from big corporations and asking her aides to leak state documents to Choi, who has no security clearance or any official title.

According to AFP, more than 50 Korean firms, including Hyundai and Samsung were allegedly coerced into donating about $65.5m (£53.8m) to two foundations linked to Choi. Most of the donations were allegedly made due to fear of harsher audits, difficulties in getting approvals for their businesses, Lee said.

He further claimed that Choi forced companies like Hyundai and Posco to give lucrative contracts to firms controlled by her. One of the presidential aides allegedly leaked 180 official documents to Choi, most of which included foreign policy documents and top official and cabinet nominations.

A spokesperson for the president declined to comment on the latest development but said that her lawyer will respond later on Sunday.

Last week, the prosecutors tried to question Park in person but her officials and lawyer asked for more time to prepare and added that they would accept a written questionnaire. The prosecutor said they could not charge the president in an official capacity for now but pledged to continue to investigate her.

Park's approval ratings plummeted to 5% in the aftermath of the scandal, the lowest for any sitting president in South Korea.