A Seoul court has extended the detention of impeached South Korean President Yoon Seok-yeol over his failed attempt to impose martial law in the country last month.

On Sunday, a judge, concerned that evidence could be destroyed if Yoon was released, issued an arrest warrant, allowing investigators to detain the suspended president for up to 20 days.

The 64-year-old president was arrested Wednesday after a weeklong standoff between investigators and his presidential security team.

After his detention was extended, the president’s supporters reportedly broke into the courthouse and smashed doors and windows, an incident condemned by Yoon and the country’s acting president.

The arrest warrant and Yoon’s subsequent decision to refuse to cooperate with investigators are the latest developments in a saga that has plunged South Korea into a political crisis.

The warrant was issued at around 03:00 local time (18:00 GMT on Saturday).

The suspended president is being investigated by the Corruption of Senior Officials Office (CIO) on charges of plunging the country into chaos following the attempted martial law order on 3 December.

He has been impeached by parliament and suspended from office, but will only be removed if the Constitutional Court upholds the impeachment.

Investigators now have 20 days, including four days since Yin’s arrest, to put the president on trial.

After extending his detention, Yoon’s lawyer told Yonhap News Agency that the president would refuse to be questioned by the chief information officer.

Pro-Yin supporters rallied outside the court ahead of the ruling, and many entered after the judge announced a delay.

Reporters at the scene reported that dozens of people were arrested by the police after the incident.

Acting President Choi Sang-mok expressed “strong regret” over the violence, which was “unthinkable in a democratic society,” adding that authorities would strengthen security for future appearances.

Choi only recently ascended to the top job after a vote in South Korea’s parliament. Impeachment of former Acting President Han Deok-soofor claiming to have thwarted Yin’s impeachment proceedings.

Yin’s lawyer said Yin was “shocked” by the scene in court and called on his supporters to express their opinions peacefully, local media reported.

The incident is the latest in a series of attempts by Yoon supporters to thwart legal proceedings against the president.

The night before his arrest, hundreds of protesters supporting Yin Camped outside the president’s residence and clashed with police who tried to detain him.

A similar scene unfolded during an earlier arrest on January 3, when Angry pro-Yin supporters hoping to stop the arrests rally outside the presidential palace.

South Korean police forced to cancel first arrest attempt The president’s security team blocked the entrance to Yin’s compound.

Public opinion became polarized afterwards Yoon’s shocking declaration of martial law last monthHe claimed it was caused by “anti-national forces” in South Korea’s parliament, while also mentioning North Korea.

But others saw the move as an extreme reaction to the political deadlock that followed the main opposition party’s landslide victory in April, and Scandal surrounding first lady makes Yoon Eun-hye unpopular.

Thousands of people have taken to the streets to demonstrate against the suspended president in the weeks since he tried to impose martial law.