Some 20,000 police officers were deployed around the South Korean capital on Saturday as 40,000 protesters turned out at the rally in central Seoul. Although police have banned protesters from marching through the streets, authorities are preparing for demonstrators to attempt to make their way towards the presidential Blue House.

In a tearful speech on Friday, Park said her "heart was breaking" over the political scandal. Her address to the nation came four days after her long-time confidante Choi Soon-sil was arrested for allegedly used her proximity to the president to influence state affairs and unlawfully direct funds to two non-profit organizations under her control.

Local media also alleged that Choi inherited her father's influence.

"It is very miserable and regrettable that a particular individual is said to have taken profits and committed several unlawful acts, while we are working on a job in hopes of helping the national economy and people's lives," Park said.

'Rasputin-like'

The president said she would allow a direct investigation into her actions, adding that she allowed Choi to assist in editing her speeches and relied on her for undefined "public relations" issues.

Park denied reports, however, that link her and Choi to a religious cult.

The South Korean media has portrayed Choi, whose late father was a shadowy religious leader and an important mentor to Park, as a Rasputin-like figure who wielded an unhealthy influence over the president.

Since the scandal erupted last week, Park's approval ratings have sunk to an all-time low for South Korea, reaching 5 percent, a 12-percent drop from last week, according to a Gallup poll published Friday.

ksb/kl (AFP, AP)