Protesters carried candles and signs reading "Who's the real president?" and "Park Geun-hye step down," as they advanced through the capital's downtown on Saturday night.

Charges that the embattled South Korean leader Park Geun-hye let longtime friend Choi Soon-sil enjoy inappropriate influence over the presidency has seen her popularity plummet to an all-time low.

"Park has lost her authority as president and showed she doesn't have the basic qualities to govern a country," Jae-myung Lee, from the opposition Minjoo Party, told protesters from a stage. Police said around 9,000 people turned out for the rally, which came hours after prosecutors raided the homes and offices of senior presidential aides accused of passing government documents to Choi.

Office reshuffle

Facing mounting pressure, Park's office announced late Friday that the president had ordered 10 of her top secretaries to quit over the corruption investigation, adding that a new lineup would be unveiled in the near future.

Earlier this week, Park issued a public apology in which she admitted giving Choi access to draft speeches for editing. The televised address sparked huge criticism about her leadership style and mismanagement of national information.

Civic groups have called for criminal charges to be brought against her aides and others who helped release government documents to Choi. The opposition Minjoo Party has demanded a thorough probe and a Cabinet reshuffle but has not raised the possibility of impeachment.

Park, 64, became the first woman to lead South Korea after she won presidential elections in 2012. Her five-year term finishes in 2018.

Choi denies interference

Choi, 60, is seen as an elusive, Rasputin-like figure in South Korea. She has no government post but is nevertheless alleged to have had enormous sway over the president's policy decisions.

In an interview with a South Korean newspaper this week, Choi denied any wrongdoing, saying she only helped Park "out of good faith." She has been holed up in Germany since September, but her lawyer says she is willing to return to South Korea if prosecutors summon her.

Choi and Park became friends in the 1970s when Choi's father Choi Tae-min, a shadowy religious figure, emerged as a mentor to Park. At the time she was serving as acting first lady after the 1974 assassination of her mother.

His alleged influence angered several key aides to her father, the country's then military strongman Park Chung-hee, who was assassinated by his spy chief in 1979.

nm/sms (Reuters, AP, dpa, AFP)