SEOUL, South Korea, Feb 20, (AP): Traveling around Seoul in a prison transport vehicle, South Korean President Yoon Suk Yeol appeared in two different courts on Thursday, contesting his arrest on rebellion charges in one and fighting an effort to remove him from office in the other. Both cases - one on criminal charges, one an impeachment - are related to his brief imposition of martial law in December.

Security was heightened at the Seoul Central District Court as the motorcade transporting Yoon arrived for a preliminary hearing that involved discussions of witnesses, proposed evidence and other preparations for his criminal trial. The court, which scheduled another preliminary hearing in March, was also reviewing a request by Yoon’s lawyers to cancel his arrest and release him from custody.

Such challenges are rarely successful. The court was expected to make a decision sometime during Thursday evening. Yoon next traveled across the capital to the Constitutional Court, which is nearing a decision on whether to formally remove him from office after was impeached by the National Assembly. Yoon was expected to face key impeachment witnesses, including Prime Minister Han Duck-soo, who has told lawmakers and investigators that Yoon sidestepped a constitutional requirement to deliberate in a formal meeting of the Cabinet before declaring martial law on Dec 3.

The court has also called Hong Jang-won, former first deputy director of South Korea’s spy agency, who has said that Yoon had ordered him to help a defense counterintelligence unit detain key politicians, including National Assembly speaker Woo Won Shik and opposition leader Lee Jae-myung. Yoon was indicted Jan. 26 on rebellion charges, which carry a potential punishment of death or life in prison.

In South Korea, presidents have immunity from most criminal prosecutions, but not on charges of rebellion or treason. The indictment alleges his imposition of martial law was an illegal attempt to shut down the National Assembly and arrest politicians and election authorities. The conservative Yoon has said his martial law declaration was intended as a temporary warning to the liberal opposition and that he had always planned to respect lawmakers’ will if they voted to lift the measure.

Yoon’s presidential powers were suspended when he was impeached Dec 14, leaving him to fight for his political life at the Constitutional Court. Martial law was lifted about six hours after Yoon declared it but has caused political turmoil, disrupted high-level diplomacy and tested the resiliency of the country’s democracy. Yoon’s conservative supporters rioted at the Seoul Western District Court after it authorized his arrest last month, while his lawyers and ruling party have openly questioned the credibility of courts and law enforcement institutions handling the case.