Secrecy squabbles disrupt Guantanamo hearing in 9/11 case GUANTANAMO BAY U.S. NAVAL BASE, Cuba (Reuters) - Secrecy disputes disrupted a pretrial hearing on Thursday in the Guantanamo war crimes tribunal for five prisoners charged with plotting the September 11 hijacked plane attacks in 2001. Defense attorneys said the audio feed to the spectators' gallery had briefly been cut, as was the feed that provides Arabic-to-English translation to the defendants, who include the alleged mastermind of the attacks, Khalid Sheikh Mohammed. The interruption came as one of the defense lawyers, U.S. Navy Commander Walter Ruiz, questioned a former commander of the Guantanamo detention operation about whether intelligence agencies or contractors were meddling with attorney-client mail that is supposed to be confidential. Ruiz referred at one point to the CIA and at another to the USDI, the undersecretary of defense for intelligence - a senior U.S. Defense Department post. Prosecutors objected to the questioning and Ruiz said the audio feed had been cut by an unseen hand outside the courtroom. Prosecutors said it had not been cut. Ruiz asked if he should refer to the CIA as "the agency who shall remain nameless." After a side conversation that was inaudible to journalists watching on monitors in the press center, Ruiz said, "I will not be threatened by prosecution and I want that to be clear." In accordance with the rules governing the tribunal, the judge called for a closed session to decide what could be discussed in open court. Spectators were ordered out and the defendants were removed, triggering a round of objections from their lawyers. Secrecy disputes have regularly sidetracked the proceedings at the U.S. naval base at Guantanamo Bay, Cuba. A previous hearing was disrupted when intelligence monitors listening from outside the courtroom cut the public audio feed, but the judge, Army Colonel James Pohl, ordered that kill switch disabled. The United States has held foreign terrorism suspects at the Guantanamo facility, which has been criticized by rights groups and others. Pohl still must decide whether the defendants can be present in the courtroom when classified information is discussed during pretrial hearings. The lawyers have said that most of the classified information relates to the years the defendants spent in secret CIA prisons between their capture in 2002 and 2003 and their transfer to Guantanamo in 2006. The agency has acknowledged that Mohammed was subjected to the mock-drowning technique known as waterboarding 183 times, and defense lawyers say all five defendants were interrogated using now-banned methods that constituted torture. Once the trial starts, which will be in late 2014 at the earliest, the defendants will be allowed to hear everything heard by the jury of U.S. military officers who will decide whether they are guilty of crimes that could lead to the death penalty, including terrorism, hijacking and murdering 2,976 people. Prosecutors argue that trial rules allow the defendants to be excluded from pretrial hearings to discuss legal arguments pertaining to classified information that could jeopardize national security if disclosed. Defense lawyers argue that the rules allow them to stay in the courtroom unless they are disruptive, and that they should be allowed to hear all the pretrial arguments in a case that could end with their execution. "Mr. Mohammed has a right to be present when we're talking about matters that deal with his torture," said Mohammed's lawyer, David Nevin. Prosecutors acknowledged that the defendants had been exposed to classified intelligence sources and methods during their time in CIA custody. The judge said that if the defendants themselves were to testify about such matters, then "obviously they'll be present for that." "If the information came from them in the first place then we can release it back to them," defense attorney James Connell clarified during Wednesday's session. He represents Mohammed's nephew, Ali Aziz Abdul Ali, who is accused of sending the September 11 hijackers $120,000 for expenses and flight training. The defendants have sat quietly during this week's hearings, flipping through court documents and chatting with their lawyers without any of the outbursts that have marked earlier hearings. All were dressed in white clothing, with turbans or keffiyehs. Mohammed wore a jungle-print camouflage jacket over his. Editing by Kevin Gray and Will Dunham