SEOUL — South Korea's impeached President Yoon Suk Yeol appeared in court Saturday to contest a request by investigators to extend his detention and to defend the legitimacy of his controversial martial law decree in December.

The Seoul Western District Court is expected to rule Saturday night on a warrant request filed by the Corruption Investigation Office for High-Ranking Officials (CIO), which is seeking to formally arrest Yoon on charges of insurrection. If approved, Yoon would become South Korea’s first sitting president to be formally arrested.

The CIO, along with police and military investigators, alleges that Yoon's martial law declaration amounted to an attempted insurrection.

Yoon was charged with leading an insurrection and abuse of power, and investigators argued that the severity of the crimes and the potential risk of recidivism warrant his continued detention.

Yoon’s legal team has argued that the CIO lacks the authority to investigate such allegations.

His lawyer, Yun Gap-keun, stated that Yoon chose to attend the hearing to clarify the legitimacy of his actions and restore his tarnished reputation.

Footage broadcast by local media showed vehicles transporting Yoon to the court under heavy security.

He remains held at the Seoul Detention Center, where he has been questioned for over 10 hours but has reportedly stayed silent on the charges.

As part of the investigation, two senior officials from the Presidential Security Service (PSS) appeared for questioning on Saturday.

Kim Seong-hoon, acting chief of the PSS, and Lee Kwang-woo, head of the bodyguard division, are accused of obstructing Yoon’s detention.

Kim was detained on Friday for allegedly leading efforts to block investigators.

In a related development, the National Assembly passed a revised bill to launch a special counsel probe into Yoon’s actions.

The opposition-led bill passed in a 188-86 vote on Friday, despite strong resistance from the ruling People Power Party (PPP).

The Democratic Party (DP), which holds a majority in the 300-member assembly, pushed the bill forward after bipartisan talks failed.

The revised bill excludes earlier allegations that Yoon had committed "treason" by attempting to provoke war with North Korea.

The case marks a historic and polarizing moment in South Korean politics, with the potential for far-reaching consequences.

If Yoon’s arrest is approved, it would underscore a dramatic shift in the nation's approach to holding sitting leaders accountable. — Agencies