President Park Geun-hye has been accused of leaking top secret state documents to her long-time confidante Choi Soon-sil. Choi does not hold any public office, and is being investigated for using her ties to Park to coerce money out of major conglomerates.

Choi was also allowed to vet Park's presidential speeches and advised her on crucial policy choices. Thousands turned up for a mass rally on Saturday afternoon in central Seoul to call on Park to step down.