A South Korean court on Sunday agreed to extend President Yoon Suk Yeol’s detention, saying there were “concerns” that Yoon would “damage evidence” in an investigation into his minor declaration of martial law in early December.

Last Wednesday, Yoon became the first South Korean president to be arrested. Investigators investigating Yoon on charges of treason asked a court in Seoul on Friday to extend his detention after he refused to be questioned.

The Western District Court of Seoul has said it will approve the arrest warrant requested by the CIO’s corruption investigation office.

The reason for the confession was “concern that the suspect would destroy evidence,” the court said.

Under the new warrant, Yoon can be detained for up to 20 days. He is being held at the Seoul Detention Center.

Meanwhile, Mr. Yoon resists the CIO’s attempt to interview him, refusing to go to the interview. It is unclear whether he will cooperate with investigators during his lengthy prison sentence.