South Korea's impeached President Yoon Suk Yeol refused to be questioned by investigators on Monday under a probe into whether he committed insurrection, as dozens of his supporters faced being charged over a violent rampage on a court building.

South Korea's impeached president, Yoon Suk Yeol, was formally arrested early Sunday, days after being apprehended at his presidential compound in Seoul, as he faces possible imprisonment over his ill-fated declaration of martial law last month.

South Korean investigators probing impeached President Yoon Suk Yeol for alleged insurrection asked a Seoul court on Friday to extend his detention after he refused to be questioned.