The Air Force has set a tentative court-martial date for an Arabic interpreter accused of spying at the Guantanamo Bay (search) prison for terrorism suspects.

Senior Airman Ahmad I. al-Halabi (search) is scheduled for a court-martial on April 20, the Air Force said Wednesday. He is charged with espionage, aiding the enemy and several lesser offenses in connection with his work at the Navy base in Cuba. Al-Halabi's lawyers say he is innocent.

The military judge in al-Halabi's case, Col. Barbara G. Brand, scheduled an arraignment for al-Halabi for Monday at Travis Air Force Base in California, the Air Force said in a statement. Al-Halabi had been stationed at Travis before being sent to Guantanamo.

Al-Halabi's court-martial also will be at Travis. He is being held in a jail at Vandenberg Air Force Base (search) in California.

Agents arrested al-Halabi July 23 as he got off a flight from Guantanamo to Florida. He is accused of gathering secrets about the base, such as the names and cell numbers of prisoners and messages from the inmates. Al-Halabi is accused of transmitting some of that information to an unidentified enemy and someone in the Middle East, possibly in Syria, his home country.

Al-Halabi's lawyers say the airman was arrested while he was about to take leave to marry his fiance in Syria.

The airman was the first of four workers at Guantanamo Bay to be arrested as part of an investigation into possible security breaches at the prison for some 660 suspected Al Qaeda or Taliban members.

A former Muslim chaplain at the prison, Army Capt. James Yee, has been charged with mishandling classified information, disobeying orders, committing adultery and storing pornography on his military computer. Military officials this week postponed a hearing in his case until next month. Yee has pleaded innocent.

A civilian interpreter, Ahmad F. Mehalba, was arrested in Boston and charged with lying to federal agents by denying computer discs he was carrying had classified information from Guantanamo. He also has pleaded innocent.

On Nov. 29, Col. Jack Farr, an Army Reserve intelligence officer on six-month assignment to Guantanamo Bay, was charged with transporting secret documents without proper containers and with lying to investigators.