By Ju-min Park

SEOUL (Reuters) - A top South Korean military commander said on Tuesday he trusted President Yoon Suk Yeol to be making a legitimate decision when he declared martial law, but declined to say if the impeached leader gave orders to "drag" lawmakers out of parliament.

Army Lieutenant General Lee Jin-woo testified at a Constitutional Court trial reviewing parliament's impeachment of Yoon, who is accused of masterminding insurrection with his short-lived martial law decree of Dec. 3.

Yoon again played down his martial law declaration, which shocked the country and plunged the industrial powerhouse and a powerful example of democratic resilience into a constitutional crisis that also saw the prime minister being impeached.

"I still believe it was legitimate and when told to go to parliament, I considered it to be an order," Lee told the court.

"There was no chance to even think about whether it was illegal or unconstitutional, when the commander in chief, who represents the people, and whom I knew to be a legal expert as a former top prosecutor, spoke to the country and to the world."

The Constitutional Court is reviewing parliament's impeachment of Yoon on Dec. 14 and will decide whether to remove him from office permanently or reinstate him. If he is removed, a new presidential election must be held within three months.

Prosecutors have separately indicted Yoon on charges of leading an insurrection. He was arrested last month and is being held at a detention centre.

Lee, who was the commander of the Army Capital Defence Command, is among a number of senior military and police officers who have been accused of insurrection and abuse of authority.

Yoon attended the court hearing on Tuesday and said there was no point in debating whether he gave orders to remove lawmakers gathering to vote to lift the martial law when "nothing actually happened."

Lee declined to answer many of the questions, including whether Yoon had ordered him to use firearms if necessary and break into parliament to remove the lawmakers, saying he was a defendant in a criminal case.

A copy of the indictment against Yoon seen by Reuters said Yoon allegedly asked the safety minister to cut off power and water to several media outlets considered to be critical of the conservative leader.

(Reporting by Ju-min Park; additional reporting by Hyunsu Yim; Editing by Jack Kim and Clarence Fernandez)