The conspiracy case against five men charged with planning the September 11, 2001 terrorist attacks got underway Saturday as the suspects ignored the military judge and disrupted the proceedings, dpa reported.
What had been expected to be a formal, brief arraignment continued well into the evening hours.
The delaying tactics indicated a long drawn-out process ahead to prosecute the suspects. The actual trial is not expected to begin until next year.
All five suspects deferred entering a plea to the charges of murder, conspiracy and other offenses.
The accused mastermind of the attacks, Khalid Sheikh Mohammed, and the four other defendants refused to wear earphones provided for Arabic translations.
They also refused to respond to any questions from the presiding military judge, Army Colonel James Pohl.
Military prosecutors are seeking the death sentence if the five suspects are found guilty of the plot to hijack and crash four passenger planes in New York, Washington and Pennsylvania. Nearly 3,000 people were killed in the attacks.
Defendant Ramzi Binalshibh interrupted the proceedings early on by kneeling to pray.
"They are trying to kill us," he shouted later.
Walid bin Attash was strapped to a chair and carried into the courtroom after he refused to enter. His lawyers said he had been abused. But Pohl allowed him to be unrestrained after he promised he would behave civilly.
After waiting more than a decade for justice, some relatives of the victims followed the proceedings via direct video link in Fort Meade, Maryland, outside of Washington DC.
"I've only seen body language that indicates they have nothing but contempt for our values and our way of life," one woman said in remarks broadcast on Al-Jazeera.
Several of the defence attorneys raised the issue of torture and abuse, which according to experts will play a large role in the trial. Mohammed was captured in 2003 in Pakistan and kept in a secret CIA prison where the intelligence agency has confirmed that he was subjected to water-boarding - a simulated drowning - 183 times.
Evidence obtained via torture is not allowed in the court.
The bearded Mohammed's silence on Saturday contrasted with his outbursts in the 2008 court session at Guantanamo, the last time he was seen in public. Mohammed, who has also claimed responsibility for the videotaped beheading of Wall Street Journal reporter Daniel Pearl in 2002, used that hearing to loudly mock the US court system and demand to be sentenced to death.
"This is what I want," he told the military judge in 2008. "I'm looking to be martyr for a long time."
Defence lawyer David Nevin said Saturday he believed Mohammed would decline to address the court.
"I believe he's deeply concerned about the fairness of the proceedings," he said.
Critics worry that the proceedings have been tainted, and the US government is under pressure to conduct them in a way that addresses concerns and ensures the legitimacy of the process.
Defendant Binalshibh belonged to the same terrorist cell in Hamburg, Germany, as the lead suicide pilot Mohammed Atta. He had planned to join the hijackers but was refused a visa by the US, according to prosecutors. The other defendants are Ali Abdul Aziz Ali and Mustafa Ahmed al-Hawsawi.
The charges include 2,976 counts of murder, terrorism, hijacking aircraft, conspiracy, attacking civilians, intentionally causing serious bodily injury and destruction of property.
The initial attempt to prosecute the case in 2008 was stopped by the administration of US President Barack Obama, who entered office in 2009 declaring he would close the Guantanamo Bay prison camp and bring suspected terrorists before civilian courts on US soil.