South Korea's suspended president attends impeachment hearing

South Korea's impeached President Yoon Suk Yeol appeared at the Constitutional Court for the first time Tuesday, and vowed to cooperate with the judges who will decide whether to remove him from office.

The country was plunged into political chaos by Yoon's December 3 martial law declaration, which lasted just six hours before lawmakers voted it down.

They later impeached him, stripping him of his duties. He also became the first sitting South Korean president to be arrested in a criminal probe on insurrection grounds.

Thousands of protesters – both for and against Yoon – flocked to the Constitutional Court, which is holding hearings to decide whether to uphold his impeachment.

"I will respond to any questions or provide further remarks if necessary," Yoon told the judge.

AFP reporters saw Yoon – who remains South Korea's official head of state – driven into the building in a blue justice ministry van from the detention centre where he is being held pending a criminal probe on insurrection grounds.

Court spokesperson Cheon Jae-hyun told reporters that Yoon's legal team have requested to call "at least 24 individuals" as witnesses, including election-related officials.

Yoon and his legal team have sought to justify his attempt to suspend civilian rule as a necessary measure due to election fraud, after the opposition won parliamentary elections by a landslide last year.

According pool reporters, he appeared in court wearing a suit – not his standard-issue prison uniform, which he has been required to wear since he was formally arrested Sunday.

Yoon's legal team said he wanted to "personally appear to explain the circumstances surrounding the declaration of martial law."

If the court rules against Yoon, he will lose the presidency and elections will be called within 60 days.

The lawyers prosecuting the case, who were selected by the parliament, told reporters before the hearing that "a prompt impeachment trial and removal of the president is the most direct path to restoring the rule of law"/

Yoon stayed away from the first two hearings last week, but the trial – which could last months – will continue even if he is absent.

Yoon has also been refusing to submit to separate questioning by the Corruption Investigation Office (CIO), the body in charge of the criminal probe into his martial law declaration.

It said it had attempted to compel him to attend but due to the "suspect's continued refusal to cooperate" they abandoned the efforts.

As Yoon is attending the impeachment trial, questioning him "will be difficult" on Tuesday, a CIO official told reporters.