By Lacey Johnson
FORT MEADE, Md. (Reuters) - A Yemeni man accused in the Sept. 11, 2001, attacks testified on Wednesday that Guantanamo Bay guards have used noises and vibrations to torment him for years, but a prosecutor questioned his mental state.
Ramzi bin al Shibh, 43, was questioned for more than two hours about the alleged abuse, which he said began a few weeks after his arrival at the U.S. Navy prison in Cuba in 2006.
"They wait for me until I go to sleep, 30 minutes, 40 minutes ... and then they start the vibrations," said Bin al Shibh, who wore a white turban and brown camouflage jacket at his pre-trial hearing in a military tribunal.
Bin al Shibh said the disturbances prevented him from concentrating, sleeping and praying. He is held at Camp Seven, the secret part of the prison where the United States keeps former Central Intelligence Agency captives.
Bin al Shibh's lawyers contend prison staff have ignored a 2013 order by Judge Army Colonel James Pohl that they stop any harassment of him. Guards have denied the abuse allegations.
Prosecutor Clay Trivett responded by questioning Bin al Shibh's mental state.
When asked about the source of the vibrations, Bin al Shibh said electronic devices in the walls and floors produce the tremors and also make banging noises. He said the devices were hidden throughout the prison.
Bin al Shibh accused guards of using them to torment him in the shower, recreation area and a conference room where he meets with his attorneys.
"So you believe that every one of the guards at Camp Seven is in on this secret to harass you, correct?" asked Trivett.
"Yes," answered Bin al Shibh.
Bin al Shibh is accused of wiring money and passing on information from al Qaeda leaders to the hijackers who slammed airliners into New York's World Trade Center, the Pentagon and the Pennsylvania countryside, killing 2,976 people. He and four alleged co-conspirators face the death penalty.
The Guantanamo Bay hearing was monitored by closed-circuit television at Fort Meade, outside Washington.
(Editing by Ian Simpson and Richard Chang)