SEOUL Impeached President Yoon Suk Yeol was formally arrested early yesterday after a court issued a warrant to detain him for an extended period over his botched martial law bid last month, marking the first such detention of a sitting South Korean president in the country's modern history.

Citing the risks of destroying evidence, a judge at the Seoul Western District Court granted the warrant on charges Yoon led an insurrection and abused his power when he declared martial law on December 3 and allegedly sent troops to the National Assembly to stop lawmakers from voting down the decree.

With the warrant's issuance, investigators can keep Yoon in custody for up to 20 days, including the days he has already spent at a detention center following his apprehension at his residence in Seoul on Wednesday.

The Corruption Investigation Office for High-ranking Officials (CIO) plans to transfer custody of Yoon to the prosecution after 10 days.

The prosecution is then expected to investigate him further and indict him before the 20 days are up.

CIO officials said that they will carry out a probe into the president "in accordance with the law and procedures."

Yoon's lawyers have said the martial law bid was an "act of governance" and cannot be subject to a court judgment as it was implemented to overcome a national crisis caused by the opposition-led impeachments of Cabinet members, gridlock in legislation and unilateral budget reduction.

After the warrant was issued, angry supporters of the president broke windows of the court and pushed their way into the court in protest, creating a commotion. Some threw a plastic chair, trash and other items at police officers surrounding the court building.

"President Yoon Suk Yeol!, President Yoon!" they shouted.

Citizens in support of Yoon's detention rejoiced when Yoon's warrant was granted.

"Indeed, legal justice lives on," one person said.

Police authorities have mobilised hundreds of personnel to ensure safety in areas where Yoon's supporters and critics staged rallies.

The court's issuance of the warrant marked a face-saving moment for the CIO as questions have persisted over its investigation capabilities, with critics underscoring the absence of substantial achievements since the launch of the body four years ago.

The CIO's ability to lead major cases was called into question when its first attempt to detain Yoon got bogged down due to the Presidential Security Service's defiant move to block the execution of the warrant earlier this month.

Yoon's presidential powers were suspended after the opposition-dominated assembly voted to impeach him on December 14.

The Constitutional Court is deliberating whether to reinstate or remove Yoon from office.

In a related move, acting President Choi Sang-mok yesterday expressed strong regret over the violence at a court following the court's decision to formally arrest impeached President Yoon Suk Yeol.

Cho ordered police to "sternly investigate the incident, which undermines democracy and the rule of law, in accordance with the law and principles" and to "hold those responsible accountable."

Choi also directed authorities to tighten security around government facilities amid the ongoing investigation into Yoon, who faces accusations of insurrection and abuse of power through the short-lived imposition of martial law on December 3.

Yoon's supporters stormed the Seoul Western District Court, vandalising facilities, throwing objects and threatening police officers. Police apprehended 45 protesters at the scene. YONHAP