In a surprise move on Wednesday, accused 9/11 mastermind Khalid Sheikh Mohammed urged the military judge presiding over his case at Guantánamo not to be swayed by broad claims of US national security invoked by prosecutors, nor by sympathy for the nearly 3,000 victims of the 2001 terrorist attacks.

“The government at the end of the argument gave you advice,” Mr. Mohammed said while seated at the defense table and speaking through an Arabic interpreter. “I would like to give you similar advice.” he said. “Any decision you take, you have to keep in mind that the government is using the definition of national security as it chooses.”

His comments came on the third of five days of hearings this week to resolve a wide range of pretrial issues – including whether the government should be permitted to suppress any potential statements by Mohammed and his codefendants about their alleged torture while in the custody of the Central Intelligence Agency (CIA).

The request from Mohammed to speak in open court was unusual. Equally unusual was Judge James Pohl’s decision to let him address the court.

Mohammed spoke for about five minutes. He told the court that while the US government mourns the loss of 3,000 victims of the 9/11 attacks, the US government had also killed “millions” in the name of protecting national security.

“Every dictator can put this definition on as a shoe that he chooses to step on every person in this world, every law, and every constitution,” Mohammed said.

“With this definition many can invade the rule and also go against it,” he said. “Many can kill people under the name of national security, and torture people under the name of national security, and detain children under the name of national security."

Mohammed added: “I don’t want to be long, but I can say the president can take someone and throw him in the sea under the name of national security.” The comment was an apparent reference to the burial at sea of former Al Qaeda leader Osama bin Laden, who was killed by US Special Forces in a raid last year.

“My only advice to you,” Mohammed said, addressing the judge, “is that you not be affected by the crocodile tears, because your blood is not made of gold, and ours out of water. We are all human beings.”

Mohammed had missed a portion of the morning session after exercising his recently granted right to waive his presence at the military commission proceedings. Three others also chose to skip the hearing on Wednesday.

But Mohammed announced later in the morning that he changed his mind. He was ushered into the courtroom after the lunch break. During the afternoon session he wore a camouflage vest, adding paramilitary flair to the short, bearded defendant’s appearance.

There was no prior warning that Mohammed had something to say. His lawyer, David Nevin, announced to the judge that his client wished to address the court.

In most cases, a defendant would be rebuffed and told to put his comments in a legal motion or a letter. But in this instance, Judge Pohl decided to let him talk.

Afterward, the judge made clear that there would be no future opportunities for defendants to address the court.

“We need to make something clear here,” Pohl said with more than a trace of irritation in his voice. “This is a one-time occurrence. If the accused wish to represent themselves as attorneys that is one issue, but however heartfelt, I am again not going to entertain any personal comments by the accused.”

The action came after a full day of debate over whether the judge should approve a protective order proposed by the government that would effectively treat certain thoughts, memories, and experiences of Mohammed and his codefendants as national security secrets. Pohl is expected to rule soon on whether any statements made by the accused terrorists concerning their rendition and alleged brutal treatment in secret CIA prisons must be handled by defense attorneys and others as if they are classified as top secret information.

Military prosecutors are seeking to block any attempt by defense lawyers to use the defendants' alleged torture while in CIA custody as a way to put the US government itself on trial at Guantánamo.

Defense lawyers argue that the government could not properly classify information retained by the defendants since their time in CIA custody because the government does not maintain control over the defendants’ thoughts and memories.

Significant details about the defendants’ treatment in so-called CIA black sites have been disclosed by the government and reported in the media, including that Mohammed was subjected to 183 episodes of waterboarding.

Human rights advocates say the technique is a form of torture. US officials deny that harsh interrogations crossed the line into torture.

The defendants were also subjected to forced nudity, extreme isolation and sensory deprivation, prolonged temperature extremes, sleep deprivation, and threats made against family members, according to government documents.

Mohammed and the others are charged with orchestrating and helping to carry out the 9/11 terror attacks on the World Trade Center and Pentagon that left nearly 3,000 dead. If convicted they face a potential death sentence.

Earlier on Wednesday, a lawyer with the American Civil Liberties Union, Hina Shamsi, urged the court to reject the US government’s broad assertion of authority in its proposed protective order.

“We are aware of no other protective order that is as radical as what the government is asking you to judicially bless here,” Ms. Shamsi said.

The government claims that the five defendants possess highly sensitive information about intelligence sources and methods by virtue of their being targets of those sources and methods. Shamsi said the government cannot involuntarily subject individuals to classified interrogation techniques and then impose a prior restraint on their ability to report potential government wrongdoing – particularly when the information is retained as memories.

“It goes without saying, but perhaps the CIA needs to hear it said. Thoughts, experiences, and ideas belong to human beings, not to the government,” Shamsi told the court.

Deputy Trial Counsel Joanna Baltes defended the government’s approach. She said the government’s proposed protective order used the same standards applied in terrorism trials conducted in federal court, including the prosecution of Ahmad Ghailani in New York City.

“It is an inflammatory allegation for the ACLU to come in here and say they’ve never seen anything like this,” Ms. Baltes said. “To suggest in this case we are violating the First Amendment is disingenuous.”

Defense lawyers disagreed.

“Simply holding someone in custody does not mean you control their thoughts and experiences and observations,” said James Connell, a lawyer for Ali Abdul Aziz Ali.

Although the trial is being conducted at a courtroom at the US Naval Base, Guantánamo Bay, Cuba, some members of the media are monitoring the proceeding via a video feed at Fort Meade, Md.