Hundreds of supporters of South Korea's arrested president, Yoon Suk Yeol, stormed a court building early on Sunday after his detention was extended, smashing windows and breaking inside, an attack the country's acting leader called "unimaginable".

A Seoul court issued a warrant Saturday to detain impeached President Yoon Suk Yeol for an extended period over his botched martial law bid last month in the first such detention of a sitting South Korean president.

Lawyers for South Korea’s impeached president say he will appear at a hearing in a Seoul court to oppose a formal arrest over last month’s imposition of martial law