Yoon was arrested in a dawn raid last week

After the court extended his detention around 3:00 am (1800 GMT Saturday), the president's supporters smashed windows and doors as they rushed inside the building.

The trial could take months, Chu said, but the separate impeachment hearing could move more quickly.

Yoon has been holed up in the presidential residence and protected by an elite guard force since being suspended and impeached last month

In scenes of high drama on Friday, Yoon Suk Yeol's presidential guards and military troops shielded the former star prosecutor from investigators, who called off their arrest attempt citing safety concerns.

Yoon has gone to ground but remained unrepentant as the crisis has rolled on, issuing a defiant message to his base days before an arrest warrant expires on January 6.

The conservative leader also faces criminal charges of insurrection, which could result in life imprisonment or even the death penalty.

Yoon said he would not seek to avoid legal and political responsibility for his decision to declare martial law for the first time in South Korea since 1980. He said the decision was born of desperation.