Zacarias Moussaoui, the only individual charged in connection with the Sept. 11 attacks, attempted to plead guilty Thursday but was stopped when the judge insisted he take a week to think his decision over.

"I am a member of Al Qaeda" pledged to Usama bin Laden, Moussaoui told U.S. District Judge Leonie Brinkema, who moments earlier had entered a not guilty plea on his behalf to a third indictment. Shortly after that, Moussaoui tried to plead guilty.

After an arraignment in which Moussaoui often argued with the judge, Brinkema insisted that Moussaoui think about his decision for a week. She scheduled a hearing for next Thursday.

"I don't need," Moussaoui said in response. "I've been thinking about it for months."

Moussaoui said, however, he wanted to fight the government's attempt to have him executed. The penalty phase normally would come after a guilty plea or conviction in a trial.

The arraignment had been scheduled after the government on Tuesday obtained a third indictment against Moussaoui following a new Supreme Court ruling on the death penalty. The new indictment added allegations that would enable the government to seek the death penalty.

Moussaoui is the only individual charged in connection with the attacks. The original indictment in December accused him of plotting with the 19 hijackers and mimicking their conduct, including enrollment in flight schools. While government officials believe he was planning to be the 20th hijacker, Moussaoui was in custody on Sept. 11 on immigration violations.

Moussaoui at first tried to enter what he called "a pure plea." He said such a plea would enable him to make specific statements regarding his participation in a known terrorist group since 1995.

When Brinkema said he was confused, Moussaoui responded, "I'm not confused, thank you."

The judge then told him his only choices were: guilty, not guilty, or no contest, and she had ruled out the latter in a previous hearing.

Moussaoui told the judge, "I don't have to take advice from you."

Brinkema then said, "I am therefore entering a not guilty plea on your behalf."

Moussaoui responded that he was pleading guilty and the judge replied that she would give him a week to reconsider.

Moussaoui went back to court Thursday on a second indictment. Charges were initially filed against him in December. In June, prosecutors dropped references to Moussaoui's interest in crop-dusting aircraft.

Moussaoui last December told Brinkema he had no plea and the judge entered a plea of innocent.

After the June revision in the indictment, Moussaoui tried to plead "no contest," but Brinkema again entered an innocent plea after explaining the term was the equivalent of pleading guilty.

Moussaoui, who is acting as his own lawyer, sat alone in the middle of three seats at the defense table. And when he stood to speak at the lectern, facing the judge, two marshals stood directly in back of him and two others stood just a few feet away.

Moussaoui and the judge had several sharp exchanges before he tried to enter the guilty plea.

After entering the not guilty plea on his behalf, Brinkema asked Moussaoui if he wanted her to set a new trial date to give him more time to prepare. Jury selection now is set to begin for Sept. 30.

Moussaoui said he wanted time to think about it, and the judge suggested that he should consult with court-appointed lawyers who remain in the case despite the judge's decision to let him represent himself.

"I don't have to consult with people who want to undermine my defense," said Moussaoui, who has accused the court-appointed lawyers of seeking to have him executed.

He told the judge, "Stop this nonsense game you are playing here. I don't have to take advice from you regarding the way I defend myself."

When the judge started to tell Moussaoui, "All right," he told her in a mocking tone, "Everything is all right. This is not justice."

When she then told him to sit down, he mockingly said, "Yes yes have a seat."

Shortly afterwards, when the judge asked whether any attorney had additional issues to raise, Moussaoui put his hand up and said, "Yes."

"I want to plead today guilty because I want to save my life," Moussaoui said, adding as he has in numerous motions that he knows who committed the September attacks. He said the guilty plea would allow him to tell what he knows.

Brinkema warned him that if she accepted his guilty plea it could not be reversed. She then insisted over his objections that he think about it for a week. Under federal law, a guilty plea does not automatically preclude the death penalty.

The judge told Moussaoui that he could negotiate with the government a plea agreement that could avoid the death penalty. But she said she has no role those negotiations.

The Associated Press contributed to this report.