Seventy men accused of plotting to stage a coup in Equatorial Guinea will be tried in jail in Zimbabwe.
The suspected mercenaries were on board a plane in Harare when they were caught
A judge ruled that Chikurubi jail, where the men are being held, was the only suitable place for a trial, because of "serious security concerns".
The men's lawyers had appealed for trial in an open court.
State prosecutors had warned the court that external groups had the capability of launching an airborne rescue mission.
The judge said that the trial venue would allow access for relatives of the accused and the media.
The men were arrested two weeks ago at Harare International Airport and charged with conspiring to murder President Teodoro Obiang Nguema of Equatorial Guinea.
The men say they are merely mine security guards.
Another 15 men are being held in Equatorial Guinea.