South Korean President Park Geun-hye has accepted the resignations of her top presidential aides, including the chief of staff, the presidential office has said, amid a deepening political crisis.

Sunday's departure of the top presidential officials comes as Park is grappling with a recent influence-peddling scandal involving an old friend, Choi Soon-sil.

Choi returned to South Korea from Germany on Sunday as the political crisis engulfed Park over allegations that she allowed Choi to use her friendship to exert improper influence and benefit personally.

Jeong Yeon-guk, a spokesman for the presidential office, announced on Sunday that three long-time Park aides had also stepped down.

South Korean protesters call for president's resignation

Park has been facing calls to reshuffle her office and cabinet after acknowledging on Tuesday that she provided longtime friend Choi Soon-sil drafts of her speeches for editing.

There's also media speculation that Choi, who holds no government job, meddled in government decisions on personnel and policy and exploited her ties with Park to misappropriate funds from nonprofit organisations.

Al Jazeera's Harry Fawcett, reporting from Seoul, said that the assumption was "that these appointments may have been influenced by Choi, and one of them is under investigation for being the means in conveying important government documents - with national security implications - to this person who has no government position or security clearance.

"That is the essence of why there is so much anger and disbelief - that someone totally unelected can have so much influence over the state of affairs."

Thousands protest

The resignations come after thousands of South Koreans took to the streets on Saturday evening calling for Park to step down.

Holding candles and signs reading "Who's the real president?" and "Park Geun-hye step down", the protesters marched through downtown Seoul after holding a candlelight vigil near City Hall.

Police estimated about 9,000 people turned out for the biggest anti-government demonstration in Seoul in months.

"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 and the mayor of the city of Seongnam, told the protesters from a stage.

South Korean protesters shout slogans with candlelight during a protest against South Korean President Park Geun-hye on the main street in Seoul [EPA]

Despite Sunday's resignations, there are still more protests planned over the next few days, Fawcett reported.

Park's ruling party has also considered calling for a national unity government, which would effectively sideline their own president.

"Just getting rid of a few aides and secretaries today is not going to stem the tide," Fawcett said.

Prosecutors on Saturday widened their investigation by searching the homes of presidential officials suspected of interacting with Choi and receiving their office files from the Blue House - the presidential office and residence.

Source: Al Jazeera News And Agencies