South Korea's Yoon set to attend his first criminal trial hearing

Seoul, South Korea - A motorcade carrying South Korea's impeached President Yoon Suk Yeol arrived on Thursday at the Seoul Central District Court, where the embattled leader is due to attend the first hearing of his criminal trial over insurrection charges.

TV footage aired by local broadcasters showed justice ministry vehicles leaving the Seoul Detention Centre where Yoon is being held before arriving at the court where lines of police buses were parked outside to ensure security.

The court will also hold a hearing to review the legality of Yoon's detention as requested by his lawyers earlier this month.

Prosecutors last month indicted Yoon after accusing him of leading an insurrection with his short-lived imposition of martial law on December 3.

The charges are unprecedented for a sitting South Korean president, and if convicted, Yoon could face years in prison for his shock martial law decree, which sought to ban political and parliamentary activity and control the media.

His move set off a wave of political upheaval in Asia's fourth-largest economy and a top U.S. ally, with the prime minister also impeached and suspended from power and a number of top military officials indicted for their roles in the alleged insurrection.

Yoon is also facing a parallel impeachment trial conducted by the Constitutional Court which has entered its final phase.

The top court will hear witnesses testify including Prime Minister Han Duck-soo later on Thursday though it is unclear if Yoon will also attend the impeachment trial hearing.

The Constitutional Court is reviewing parliament's impeachment of Yoon on December 14 and will decide whether to remove him from office permanently or reinstate him.

Yoon and his lawyers have argued at the hearings that he never intended to fully impose martial law but had only meant the measures as a warning to break a political deadlock.

If Yoon is removed, a new presidential election must be held within 60 days.

(Reporting by Hyunsu Yim; Editing by Ed Davies)