Jurors deciding the fate of Zacarias Moussaoui are being exposed to some emotionally jarring testimony as the al-Qaida terrorist's death-penalty trial moves into a second phase.

In this photo released by the Sherburne County Sheriff's Office, Zacarias Moussaoui is shown in this August 2001 photo. [AP]

On Wednesday, prosecutors received the judge's approval to play cockpit voice recordings from United Flight 93, the plane that crashed into a western Pennsylvania field on Sept. 11, 2001, after passengers fought back against the hijackers.

The tape has never been aired publicly, although relatives of the Flight 93 passengers have been permitted to hear it. When family members heard the 30-minute recording in April 2002, the government had grief counselors on hand and warned the families that graphic details would be audible.

While the recording will be played for the jury and the courtroom gallery, it is unclear whether it will be publicly released. Most court exhibits are being made available to the public, but U.S. District Judge Leonie Brinkema is giving Flight 93 family members until Tuesday to request that the recording be kept under wraps.

Moussaoui, 37, is the only person charged in this country in connection with the Sept. 11, 2001, attacks. On Monday, a jury concluded that Moussaoui was directly responsible for at least one death on that day and is therefore eligible for execution.

He was in a Minnesota jail on 9/11. Nevertheless, the jury concluded in the first phase of the trial that Moussaoui could have thwarted or at least minimized the attacks if he had confessed his al-Qaida membership and his plan to hijack aircraft when federal agents arrested him in August 2001 after his efforts to obtain flight training aroused suspicion.

The second phase of the trial, which begins Thursday, will include evidence on whether Moussaoui deserves to be executed. Prosecutors intend to present testimony from relatives of 9/11 victims on the personal toll exacted by the attacks. They have indicated they will have up to 45 victim-impact witnesses and they plan to identify each of the 2,972 people killed that day by name and photograph to the jury.

Former New York Mayor Rudy Giuliani was expected to testify, according to CNN. Giuliani's spokeswoman Sunny Mindel declined to confirm or deny the report.

The defense has indicated it will try to present evidence that Moussaoui, a Frenchman of Moroccan descent, suffered a difficult childhood, punctuated by racism. They also will seek to introduce evidence of mental illness. A defense expert has said Moussaoui most likely suffers from schizophrenia.

The jury will be asked to balance aggravating and mitigating factors in determining whether to sentence Moussaoui to death or life in prison.