Former President Yoon Suk Yeol defended himself during his first criminal trial on insurrection charges Monday, saying his attempt to impose martial law in December did not amount to an insurrection.

Axar.az reports, citing Yonhap, Yoon arrived at the Seoul Central District Court in a black security vehicle and entered via the underground parking to avoid public exposure.

The first hearing got under way shortly before 10 a.m., with Yoon seated in the defendant's seat in a navy suit. Photography and filming by the press were not allowed under a court order.

Yoon, a former top prosecutor, faces charges of leading an insurrection through his brief imposition of martial law on Dec. 3 that saw the deployment of troops to the National Assembly in an alleged attempt to stop lawmakers from voting down the decree.

He was impeached by the National Assembly days later and removed from office on April 4 after the Constitutional Court unanimously upheld his impeachment.

"The indictment simply lists the details of the investigation into what happened during the several hours between 10:30 p.m. Dec. 3 and 2 to 3 a.m.," Yoon said after the prosecution presented a summary of its charges.

"It goes against legal principles to build an insurrection case based on an indictment that looks like a printout of an incident that lasted only a few hours and was lifted immediately in a nonviolent manner upon accepting the National Assembly's demand to lift it," he added.

The prosecution maintained, however, citing the former president's views of state affairs and his preparations in the run-up to the martial law declaration, that he intended to "start a riot" with the aim of "subverting the Constitution."

Insurrection is a crime that carries a maximum penalty of life in prison or death.

Since his ouster, Yoon has moved out of the official presidential residence in Seoul's Hannam-dong and returned to his private residence located a 10-minute walk from the court.

Two military officers will be questioned as witnesses during Monday's hearing.