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.

As South Korean authorities extended President Yoon Suk Yeol's detention, his supporters stormed the courthouse that issued the warrant, smashing windows with police shields.

Since police broke up a crowd of Yoon's supporters blocking the court gate in the morning, thousands of supporters surrounded the court after the hearing began at around 2 p.m. (0500 GMT) behind a police barricade chanting "release the president".