Egypt has begun the trial of former president Hosni Mubarak, who was in the courtroom Wednesday nearly six months after he was toppled in an 18-day revolution calling for democratic reforms.

Mr. Mubarak categorically denied all of the charges against him at the hearing in Cairo. During the proceedings he was reclined on a hospital bed inside of a large cage that was built in the front of the courtroom to house all of the defendants.

The former Egyptian leader is accused of ordering the killing of anti-government protesters during the revolution that deposed him. Nearly 900 people were killed during the uprising.

Mr. Mubarak faces a possible death sentence if convicted. He is also charged with corruption, abuse of power and squandering public wealth.

His two sons, Alaa and Gamal, also went on trial Wednesday, standing next to Mr. Mubarak and speaking to him during the hearing. Both men denied the charges against them.

Crowds gathered outside the building and watched the proceedings on a large screen. Hundreds of police were deployed outside, where at one point supporters and opponents of Mr. Mubarak threw stones at one another.

The other defendants who went on trial Wednesday include Mr. Mubarak's former interior minister , six police commanders, and a prominent businessman who is being tried in absentia.

Mr. Mubarak has been living under house arrest at the Red Sea resort of Sharm el-Sheikh with his family.

Egypt's judiciary had moved the location of the trial to the Cairo Police Academy due to security issues.