The US government on Monday pushed for an acceleration of preliminary hearings in the case of five alleged 9/11 plotters as the proceedings resumed in Guantanamo Bay.

Lead prosecutor Brigadier General Mark Martins told the court he hoped to see progress "this week" after prosecutors filed a motion calling for a September 2014 trial date.

Self-declared 9/11 mastermind Khalid Sheikh Mohammed -- wearing camouflage garb and his beard tinted with henna -- appeared in the military court at the US prison in Cuba with his four co-defendants.

All face the death penalty if convicted of plotting the 2001 attacks on New York and Washington, which left nearly 3,000 people dead. Preliminary hearings in the case began in May 2012.

"The current practice of being in court for five days approximately every six weeks is inefficient and will result in litigation that is unnecessarily prolonged, and does not serve the interests of justice," the prosecutors' motion said.

Defense lawyers countered, however, that their efforts had been hindered by a variety of factors.

The hearings have been delayed due to storms and problems in retransmitting the proceedings from the US prison in Cuba to the Fort Meade military base outside Washington.

David Nevin, who represents Mohammed, said Internet problems were slowing down defense efforts. "We can't handle discovery correctly," he said.

Cheryl Bormann, lawyer for Walid bin Attash, called for the hearing to be suspended, saying her client was unwell. Walter Ruiz, who represents Saudi national Mustapha al-Hawsawi, cited his client's "neck condition."

"Please hear the difficulties we have... the situation has deteriorated," Bormann told the court, asking Judge James Pohl to look into the problems in attorney-client communications.

"When is it going to end?" Pohl asked.

In their scheduling motion, prosecutors have called for the trial to begin on September 22, 2014.

"Lots of work has been done," Martins said, urging the court to stick to the timetable set out by prosecutors.

"The government has provided approximately 185,000 pages of unclassified discovery to defense counsel for each accused, so that the accused may meaningfully confront the charges against them," Martins said late Sunday in a statement.

Defense lawyers countered that nearly 80 percent of the documents provided by the government were about the 9/11 attacks themselves and not about the conditions under which the accused have been detained.

"There is no justification for artificial deadlines and restrictions," wrote attorney James Connell, who represents Mohammed's nephew Abd al-Aziz Ali, also known as Ammar al-Baluchi.

The five defendants were held incommunicado in secret CIA prisons from 2002 to 2006, before they were transferred to Guantanamo.

The detainees' treatment has come under close scrutiny. Mohammed is known to have been subjected to 183 sessions of waterboarding, the technique of simulated drowning which has been decried as torture by rights groups.

Connell has said he plans to file a motion on the conditions for detainees including his client at Camp 7, Guantanamo's top security facility.

When asked about Connell's intentions, a Pentagon spokesman said: "The US government takes very seriously its obligation to provide humane care and custody of detainees, consistent with the Geneva Conventions."