A court on Tuesday issued an arrest warrant for former South Korean Defense Minister Kim Yong-hyun on charges of helping President Yoon Suk Yeol stage an insurrection through his short-lived imposition of martial law last week, Yonhap News Agency reported.

The Seoul Central District Court issued the warrant at the request of the prosecution, who accused Kim of engaging in "essential" activities in insurrection and abuse of power in connection with Yoon's declaration of martial law last Tuesday.

The warrant's issuance marks the first court decision in an expanding investigation into the martial law case.

Kim forwent a court hearing earlier Tuesday that reviewed whether to issue the warrant, saying through his legal counsel that he deeply apologized for causing great anxiety and inconvenience to the people.

Prosecutors have questioned Kim three times since he was taken into custody Sunday after he voluntarily appeared for the investigation.

Kim reportedly conceded during questioning that he proposed martial law to Yoon but claimed his actions were neither illegal nor unconstitutional.

With Kim's formal arrest, the prosecution's investigation into Yoon is expected to pick up pace. Yoon has been booked as a suspect in the martial law case on insurrection charges and barred from traveling overseas.

By law, the ringleader of an alleged insurrection could face the death penalty or imprisonment for life. Those who participate in plotting an insurrection or engage in other "essential" activities could be punished by death, with life imprisonment or a prison term of at least five years.