South Korean prosecutors said Sunday that President Park Geun-Hye had colluded with her close confidante in a corruption and influence-peddling scandal that has sparked massive nationwide protests and calls for her impeachment.

Park's longtime friend Choi Soon-Sil was charged Sunday with coercion and abuse of power, as was one of the president's former aides.

Another presidential aide was charged with leaking confidential state documents.

"The president played a collusive role in a considerable portion of the criminal activities involving the (three) people," said Lee Young-Ryeol, a Seoul prosecutor who is leading a probe into the scandal. 

Choi, 60, has been accused of using her personal ties to Park to meddle in state affairs and of coercing local firms to "donate" more than $60 million to dubious non-profit foundations. She allegedly then used some of the funds for personal gain.

Park faces allegations that she helped Choi extract money from the firms and that she ordered her aides to leak state documents to Choi, who has no official title or security clearance. 

Under the constitution the incumbent president cannot be charged with a criminal offence except insurrection or treason. But she can still be probed by prosecutors and possibly charged after leaving office. 

Lee acknowledged that prosecutors could not formally charge Park at present but vowed to continue to investigate her. 

Prosecutors had previously described the conservative leader as a witness to Choi's crimes but changed her status to that of a criminal suspect, said a senior prosecutor at the investigative team. 

"From now on, she will be probed as a suspect... for violation of Section 30 of the criminal code on collusion," Roh Seung-Kwon told reporters. 

- Impeachment calls -

The latest revelations piled pressure on opposition party lawmakers to seek the impeachment of Park, the daughter of a former president, who has about a year left in her five-year term.

Presidents serve only a single term in South Korea. 

The main opposition Democratic Party has not seriously pushed for Park's impeachment due to fears of a backlash from conservative voters before the presidential election in 2017. 

But recent opinion polls suggest growing support for Park's impeachment, with the latest survey showing 74 percent backing. 

Park has promised to answer prosecutors' questions -- a move which would make her the first South Korean president to be quizzed by prosecutors while in office. 

More than 50 local firms including Samsung and Hyundai were forced to donate a total of 77.4 billion won ($65.5 million) to the two foundations controlled by Choi.  

Many made the donations due to fear of political reprisals, such as harsh tax audits or difficulties getting regulatory approvals for their businesses, prosecutor Lee said.

Choi also pressured major firms including the South's largest carmaker Hyundai and top steelmaker Posco to award lucrative contracts to firms linked to her, he added. 

One of the aides leaked 180 confidential documents to Choi including papers on foreign policy and the nomination of top officials and cabinet members, according to prosecutors.

The scandal has sent Park's approval ratings plunging to five percent -- the lowest for any sitting South Korean president. 

The ever-widening probe also shed light on questionable ties between Choi's family and the South's largest and most powerful business group, Samsung. 

Samsung, which made the biggest donation to Choi's foundations, is accused of separately offering 2.8 million euros to Choi to bankroll her daughter's equestrian training in Germany.

It is also accused of offering donations to a dubious foundation run by Choi's niece, who is seen as her key aide and is facing formal arrest by prosecutors.

Many senior Samsung officials, including the group scion Lee Jae-Yong, have been summoned to prosecutors to answer their questions.    

Choi is a daughter of a shadowy religious figure who was a longtime mentor to Park until his death in 1994. He is known to have befriended Park after the assassination of her mother in 1974. 

Source: AFP