South Korean investigators probing President Yoon Suk Yeol for alleged insurrection asked a Seoul court on Friday to extend his detention as the embattled leader again refused to be questioned.

On Wednesday, Yoon became the first sitting South Korean president to be arrested, in a criminal probe related to his short-lived declaration of martial law in early December. He is being held at the Seoul Detention Center.

In order to hold Yoon in custody for longer, investigators at the Corruption Investigation Office for High-ranking Officials (CIO) need a court to approve a detention warrant for up to 20 days.