A senior Guantanamo official says the FBI installed hidden microphones that have sparked fears of eavesdropping among defense attorneys in the Sept. 11 case.

Army Col. John Bogdan says the FBI set up the sound system in the meeting rooms for use by its agents at the U.S. base in Cuba. Bogdan, who is in charge of detention operations, testified that the military does not use the microphones to monitor private conversations between prisoners and lawyers.

He told the court he wasn't even aware of the microphones that look like smoke detectors until defense lawyers recently discovered them. He testified Wednesday in a hearing to determine if the government has eavesdropped on the defense in the Sept. 11. The issue has dominated a four-day pretrial hearing in the case.