Former president has been indicted on additional charges as a special prosecutor continues investigations.
Disgraced former South Korean President Yoon Suk-yeol has been indicted over his declaration of martial law last year as investigators widened an insurrection probe.
The prosecution indicted Yoon on charges including abuse of power and obstruction of special official duties, prosecutor Park Ji-young told reporters on Saturday.
Park said Yoon also did not follow the required procedure to declare martial law, including holding a meeting with all government cabinet members.
He was also charged with “drafting and discarding a false document” that stated the prime minister and defence minister endorsed martial law.
Yoon has denied all wrongdoing.
He plunged South Korea into a political crisis when he sought to subvert civilian rule in December, sending troops to parliament in a bid to prevent lawmakers from voting down his declaration of martial law.
Yoon became the first sitting president in the country to be taken into custody when he was detained in January after resisting arrest for weeks, using his presidential security detail to thwart investigators.
He was released on procedural grounds in March even as his trial on insurrection charges continued.
Last week, he was detained again after an arrest warrant was issued over concerns he might destroy evidence in the case.
Yoon appeared in court on Friday at a hearing to argue for his arrest warrant to be cancelled.
The ex-president’s legal team told reporters Yoon defended himself for more than 30 minutes and noted his “limited physical mobility and the challenges he was facing”.
The court denied the request.
State prosecutors have already indicted Yoon on other criminal charges, including masterminding a rebellion, a charge with conviction carrying only two sentences — capital punishment or life imprisonment.
Meanwhile, a demonstration with thousands attending took place in the South Korean capital, Seoul, as well as other parts of the country against the policies of current President Lee Jae-myung.
Lee won a snap election in June after Yoon was removed from office.
Many South Koreans are angry because they believe the new government has not addressed their concerns in its reform plans.