The trial of former president Hosni Mubarak resumed in a tension-filled courtroom in Egypt’s capital Monday, with prosecutors starting to explain charges of corruption and of complicity in the killing of protesters during the Egyptian revolution this year.

Four top security officials were on the docket to testify about Mubarak’s alleged role in ordering the shooting of protesters in January and February.

Emotions about the ousted leader and the revolution still run hot. Opposing camps of lawyers inside the courtroom got into a fistfight before the testimony began, according to Gamal Eid, a lawyer for victims’ families and a human rights activist, who sent a Twitter message from inside the courtroom. As one group of lawyers chanted loyalty to Mubarak, protesters shouted that they wanted him executed. Security forces rushed into the courtroom to restore order.

Mubarak, 83, was wearing a silver sateen tracksuit, covered by a pink blanket, as he was wheeled from an ambulance into the building on a hospital bed in images shown on state television.

Defense lawyers asked the first witness, Gen. Hussein Moussa, the former head of communications for central security, about the number of weapons and officers deployed during the protests and about who had issued orders to shoot, according to state television.

Moussa said that he had not heard direct orders for security forces to fire on protesters, surprising the prosecution, according to news agencies, and potentially weakening their case. Orders were given to use tear gas and rubber bullets, and to use live fire only to defend security buildings, he said. Shocked prosecutors said that differed from the version he had given them in an affidavit.

Mubarak’s appearance last month in a hospital bed inside an iron cage set up in a courtroom designed especially for him riveted millions across the country, where it was a testament to how much had changed in the six months since his nearly 30-year rule was toppled. Even after his ouster, many here doubted he would ever face justice.

The trial is no longer being televised. Judge Ahmed Refaat angrily ordered it off the air last month, saying he was doing so “for the sake of the public.” That order disappointed many in Egypt who wanted to see the wheels of justice turn. Several people outside the courtroom said Monday that they worried the decision was a ploy to help Mubarak and other former top officials escape accountability.

Outside the courtroom, dozens of pro-Mubarak demonstrators carried large posters of his face, once ubiquitous across the country but now absent from public spaces. Anti-Mubarak demonstrators — many of whom were family members of the more than 900 people who were killed during 18 days of demonstrations in January and February — carried pictures of the victims. They were far outnumbered by the hundreds of black-clad riot police who guarded the building and attempted to keep the rock-throwing groups separated from each other.

Many of the anti-Mubarak demonstrators said they were concerned that the former president would be exonerated.

Those now in power “aren’t concerned with us, only with their own personal affairs,” said Fathy Abdelgawad, the father of a protester who was killed in Alexandria. “I’m a martyr’s father coming to watch the charade continue.”

Mubarak, who pleaded not guilty last month, is the only Arab leader in modern history to be put on trial in front of his people, with the exception of former Iraqi president Saddam Hussein. Former Tunisian president Zine el-Abidine Ben Ali, living in exile in Saudi Arabia, was convicted twice in absentia. Libya’s recently deposed leader, Moammar Gaddafi, is in hiding, though he has been indicted by the International Criminal Court in The Hague.

Hassieb is a special correspondent. Staff writer James V. Grimaldi contributed to this report.