|Previous sessions of the trial have been held amid chaotic scenes, with protesters gathering outside the court [AFP]
The fifth session in the trial of the former Egyptian president, Hosni Mubarak, has begun in Cairo.
State television aired footage of Mubarak being carried on a stretcher into the Police Academy, where the trial is under way.
Two witnesses from the Central Security Forces were to testify on Thursday.
According to state television, one of the witnesses blamed the former interior minister, Habib el-Adly, and his aides for the killing of protesters during the 18-day uprising that led to Mubarak's downfall in February
The judge has also summoned the top members of Egypt's ruling military council to determine the toppled leader's role in putting down protests against his rule earlier this year.
When the trial resumes on Sunday, the court will hear Field Marshal Mohammed Tantawi, who now rules Egypt.
"What is expected, is that the field marshal's testimony, as well as Sami Anan [Armed Forces chief of staff] and the remaining witnesses will be the backbone of the evidence against Mubarak; had he given orders to shoot
or not and did he in fact know everything about the happenings of the revolution or not," Mohamed Mahmoud, a prosecution lawyer, said.
Testifying at the landmark trial could give Tantawi a chance to boost his image in the face of growing public criticism that the military remains too close to Mubarak's regime.
It also injects new seriousness into a trial that many saw as running aground amid confusion and allegations of perjury.
The 83-year-old Mubarak is on trial on charges of complicity in the deaths of protesters.
The sessions are closed to the media and the public, and the judge has banned Egyptian media even from reporting on information leaked from the testimony.
Among the others summoned by the court is Omar Suleiman, who was appointed vice-president by Mubarak during the uprising and was his powerful intelligence chief and a close aide for nearly two decades.
Protesters have grown increasingly critical of the Armed Forces Supreme Council's management of the post-Mubarak transition and accuse Tantawi and other top brass of failing to cut ties with remnants of Mubarak's regime.
Protesters have called for a large-scale rally - their first in more than a month - for this Friday, dubbing it "Correcting the Course," to call for an end to military rule, among other demands.
Tantawi has said in earlier public comments that the military refused to fire on protesters - a sign many read as meaning he refused orders to do so from his commander-in-chief.
But Tantawi has also appealed for the public to "leave the past aside", seen as a sign he wants leniency for Mubarak.
If the trial brings evidence of a direct order from Mubarak for lethal force to be used, that would boost pressure for a death sentence if convicted.
But if responsibility is seen as less direct - such as a failure to try to stop killings - a conviction would likely bring a lighter sentence.
Mubarak has denied any responsibility for himself or his security forces.
He told investigators before the trial that there was "chaos" and that police and protesters were attacking each other. When asked why he did not stop the violence, he said, "No one would have paid any attention to me or my orders.''
On trial with him, facing the same charges, are el-Adly and six senior security officials. Mubarak and his two sons, Alaa and Gamal, also face corruption charges.
In sessions on Wednesday and Monday, the first five prosecution witnesses, who were all senior security officers, came under suspicion of altering their testimony.
Based on earlier accounts, prosecutors had expected them to directly confirm that orders were issued to shoot protesters with live ammunition but instead they denied knowledge of such orders.