A frail but defiant former Egyptian president Hosni Mubarak denied the serious charges against him as his trial got underway in a Cairo court on Wednesday, before he was taken to a hospital on the outskirts of the city.

Mubarak, 83, was wheeled into court on a hospital bed. He was locked inside a metal cage along with his two sons and seven other co-accused.

Images of the ashen-faced leader were broadcast to millions of viewers in Egypt, as the trial's opening day was carried live on state television. Still others gathered in the sweltering heat outside the courthouse to condemn the former leader.

"The biggest achievement of this revolution is that all these crooks and scum are in a cage," said Mohammed Mustafa El-Aqqad, who lost a child in the protests. "We're here to tell Hosni, ‘Happy Ramadan. Congratulations on your new cage.'"

Outside the courthouse, Mubarak supporters chanting, "We love you Mubarak" clashed relatives of slain protesters as police in riot gear tried to keep them apart. More than 50 people were injured in the scuffles.

Mubarak, his former Interior Minister Habib el-Adly, and six other top police officers face charges in connection with the killing of peaceful protesters in an uprising that began in February.

The charge sheet alleged that Mubarak "allowed (el-Adly) to use live ammunition" in dealing with protesters.

A prosecutor read the charges against Mubarak, which accused him of being an accomplice along with al-Adly in the "intentional and premeditated murder of peaceful protesters."

Separately, Mubarak and his sons Gamal and Alaa face corruption charges related to the alleged gift of five villas worth nearly $7 million from a prominent businessman. Prosecutors allege Hussein Salem gave them the villas in return for help getting a lower price on state land to build a resort complex in Sharm el-Sheikh.

The two sets of charges have been lumped together in a mass trial which formally began on Wednesday.

When the judge asked Mubarak to identify himself, he replied, "Yes, I am here."

"I deny all these accusations completely," the defiant Mubarak then told court, while wagging a finger from his hospital bed.

Much of Wednesday's proceedings were taken up with procedural motions and other formalities, including a request from Mubarak's lawyer that Defence Minister Hussein Tantawi be called to testify. The defence lawyers argue that Tantawi, who is head of the council of generals that is now in charge, was responsible for security after January 28, three days after the protests began.

At the conclusion of Wednesday's proceedings, the judge adjourned the trial of Mubarak and his sons to Aug. 15. Mubarak was ordered held at the International Medical Center, a military hospital on the fringe of Cairo.

He also ordered that an oncologist be among the doctors on Mubarak's medical team -- the strongest indication yet that Mubarak has cancer.

The high-profile trial of the man who ruled Egypt with an iron fist for decades seemed unfathomable only months ago.

But the pressure on the Mubarak regime grew quickly after the February uprising ignited and eventually he was forced from power.

Since April, Mubarak has been held under arrest at a hospital in the Red Sea resort of Sharm el-Sheikh, where he has been treated for heart problems. His lawyer has claimed the aging former president has failing health and is extremely depressed.

Ahmed Khalifa, an Egyptian activist living in Canada, said the trial "represents great progress" for Egypt.

"I understand there is sympathy for him from older generations who don't know any different, who feel that the demands of the protesters are way too much. …but the young generation is pushing forward," Khalifa told CTV News Channel.

"I think the new generation is already leading Egypt and it's very optimistic."

Mostafa el-Naggar, an activist who helped organize the uprising, said the prospect of putting Mubarak on trial was once "a moment no Egyptian thought was possible."

On Wednesday, el-Naggar said he felt the trial was "a real success for the revolution, and I feel that the moment of real retribution is near."

Others remembered the hundreds of people who died during the uprising, those who did not live to see the day that Mubarak would face criminal charges in an Egyptian court.

"I am delighted that I see them in a cage. I feel that my son's soul is finally starting to be at rest and that his blood will cool," said Saeeda Hassan Abdel-Raouf, the mother of a 22-year-old man who died in the uprising.

Nabil Hassan, a 65-year-old newspaper seller, spat on a picture of Mubarak that ran on the front page of one of the publications displayed on his newsstand in Tahrir Square.

"When he is in the cage and we know he is there, then we know we have started to put our feet on the path of justice," Hassan said.

"If he and his accomplices are in court, he becomes one of the people, no different from anyone else facing justice. I have faith in Egyptian judges."

While many like-minded Egyptians seeking reform were pleased to see Mubarak put on trial, there were others who spoke out against the prosecution of their former leader.

"He is our president and he is going to be found innocent," said Tahami Luteifi, a woman who was one of hundreds of Mubarak supporters who gathered Wednesday outside the police academy where the courtroom is located.

Lawyer Fathy Abul-Hassan, who is representing many of the victims' families in court, said the sight of the frail leader may rally some Egyptians to his cause.

"The defence strategy is to milk whatever sympathy Egyptians may still have for an 83-year-old, bedridden leader," he said. "It is an obvious ruse."

With files from The Associated Press