Acting President Choi Sang-mok speaks during a meeting with senior government officials in Seoul, Jan. 16. Yonhap

Acting President Choi Sang-mok on Sunday expressed strong regret over the violence at a court following the court's decision to formally arrest impeached President Yoon Suk Yeol.

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

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 Dec. 3.

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