SEOUL, Korea, Republic Of - South Korean prosecutors have formally charged an old friend of President Park Geun-hye who has been suspected of manipulating power from the shadows and exploiting her presidential ties to amass an illicit fortune.

The indictment of Choi Soon-sil on Sunday came as prosecutors are preparing to question Park, which could happen in the next few days.

Prosecutors also indicted two former presidential aides who allegedly conspired with Choi.

Choi, the daughter of a late cult leader who emerged as Park's mentor in the 1970s, has been suspected of interfering with state affairs and bullying companies into giving tens of millions of dollars to foundations she controlled.

Park is facing growing calls to resign over the scandal critics say has undermined the country's democracy.