ANKARA

South Korea's impeached President Yoon Suk Yeol again refused to appear before investigators for questioning after he was formally arrested over the failed imposition of martial law last month, his lawyer said Sunday.

It came hours after investigators probing the impeached president asked him to appear for questioning later in the day, hours after a court approved his formal arrest.

The Corruption Investigation Office for High-ranking Officials (CIO) said it had requested Yoon to appear for questioning at 2 p.m. local time (0500GMT).

Yoon's lawyer, Yun Gap-geun, told the Seoul-based Yonhap News that the disgraced president will not comply with the request for questioning by the CIO.

Yoon was formally arrested on Sunday morning after a Seoul court allowed the arrest warrant requested by the investors.

In a statement issued earlier in the day, the CIO, which has faced challenges in investigating a defiant Yoon, expressed "deep regret" that he "appears to deny the rule of law" without any effort to "resolve the issue within the judicial system."

"If he can't accept the warrant issuance, he could follow the appeal or remedy process to overturn it within the judicial system," it added.

Dozens detained over violence

South Korean police have taken dozens of supporters of the country's impeached President Yoon for resorting to violence during a protest demonstration outside a Seoul court on Sunday.

Another 45 protesters were taken into custody on Sunday after storming the court in an angry protest against the decision to formally arrest Yoon, Yonhap News reported.

They were part of 44,000 protesters who gathered in a display of solidarity outside the Seoul Western District Court that granted the warrant for the president's extended detention, citing the risk of evidence destruction related to allegations of insurrection and abuse of power.

Minutes after, a group of protesters stormed the court by climbing over walls and breaking windows while hurling plastic chairs, trash, and other objects, and spraying a fire extinguisher at police officers stationed around the building, the police said.

Police have detained 86 protesters since Saturday and formed a special investigation team to probe the incident and determine further actions against those involved.

Acting President Choi Sang-mok expressed "strong" regret over the violence at the court, directing authorities to tighten security around government facilities amid the ongoing investigation into Yoon.

"I strongly regret the violence that is unimaginable in a democratic society," Choi said in a statement.

For his part, Yoon, in a letter from the detention center, urged his supporters to use "peaceful means of expression," while protesting his arrest.