If Yoon continues to refuse the investigation, the CIO may consider compulsory measures such as transferring him from the detention center for questioning or conducting the investigation directly at the detention center.

SEOUL, Jan. 19 (Xinhua) -- South Korea's detained President Yoon Suk-yeol refused to attend a scheduled detention investigation Sunday afternoon, according to local reports.

The Corruption Investigation Office for High-ranking Officials (CIO) said that Yoon did not appear for the detention investigation scheduled for 2 p.m. local time Sunday. The state anti-corrupt agency will request Yoon's attendance again at 10 a.m. local time on Monday.

If Yoon continues to refuse the investigation, the CIO may consider compulsory measures such as transferring him from the detention center for questioning or conducting the investigation directly at the detention center, according to Yonhap News Agency.

The Seoul Western District Court approved the detention warrant in the early hours of Sunday, making Yoon the first sitting president in South Korea to be detained for investigation.

After the approval of the warrant, some of the enraged supporters of Yoon stormed the court building by climbing over walls and breaking windows.

They vandalized facilities inside the court, threw trash and other objects, and threatened police officers. The number of violators who were apprehended at the scene was 86, according to multiple media outlets.

The riot prompted the country's acting President Choi Sang-mok to order a stern investigation into the violence. Choi said in a statement that the government expressed strong regret over illegal violence, which is unimaginable in a democratic society.

He ordered police to sternly investigate the incident, vowing to hold violators legally responsible and instructed relevant authorities to tighten security around relevant facilities and thoroughly manage protest rallies against Yoon's extended detention.

The country's top court also denounced the violence of supporters for the arrested president as a grave "challenge to the rule of law."

Chun Dae-yup, the national court administration chief under the direction of the Supreme Court, said in a statement that the top court expressed serious concerns and strong regret over the intrusion of some protesters into the Seoul Western District Court.

Chun stressed that it was the general denial of and the grave challenge to the rule of law, which should never happen and be tolerated, adding that it should be followed by doing thorough fact-checking and holding violators strictly accountable.

Yoon, who has been detained on charges of ringleader of insurrection, said in a statement through his legal team that he fully understood the frustration and anger of his supporters, but he urged them to express opinions peacefully.

According to local media reports, some of Yoon's supporters gathered again in front of the Seoul Western District Court Sunday afternoon. Meanwhile, some others reportedly marched toward the constitutional court.