Law enforcement authorities on Friday requested a court warrant to formally arrest South Korea’s impeached president, Yoon Suk Yeol, who was in his third day at a detention center after his lawyers failed in a last-minute effort to secure his release.

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.

Yoon Suk Yeol, who was detained for questioning over his attempt to impose martial law, would become the first sitting South Korean president to be formally arrested.