CAIRO – Egyptian police fired tear gas Sunday in an attempt to free a guard from rioting detainees, killing at least 36 as the country’s military leader vowed to tolerate no more violence after four days of clashes that killed nearly 900 people.

The deaths of the prisoners, captured during the fierce fighting in recent days around Cairo’s Ramses Square, came as Gen. Abdel-Fatah el-Sissi also called for the inclusion of Islamists in the government.

Meanwhile, security forces detained Muslim Brotherhood members in raids aimed at stopping more planned rallies supporting ousted President Mohammed Morsi — which the military-backed government says fuels the violent unrest.

The suspects killed were part of a prison truck convoy of some 600 detainees heading to Abu Zaabal prison in northern Egypt, security officials told The Associated Press. Detainees in one of the trucks rioted and managed to capture a police officer inside, the officials said,

Security forces fired tear gas into the truck in hopes of freeing the badly beaten officer, the officials said. The officials said those who died were suffocated by the gas.

However, the officials’ version contradicted reports about the incident carried by state media. The official website of Egyptian state television reported that security forces fought with militants near the prison and detainees came under fire while trying to escape.

State media also said all those killed and the gunmen belonged to the Muslim Brotherhood, the organization that Morsi hails from. The officials who spoke to AP said some of the detainees belonged to the Brotherhood, while others didn’t.

The fighting began Wednesday when security forces dismantled two encampments in Cairo of Morsi supporters, who demanded his reinstatement.

Security forces arrested hundreds of Muslim Brotherhood members early Sunday in raids on their homes in different cities, aimed at disrupting planned rallies to support Morsi. The Cabinet also held an emergency meeting to discuss potentially banning the group, a long-outlawed organization that swept to power in the country’s first democratic elections a year ago.

That likely would diminish the chances of a negotiated solution to the crisis and again push the group underground.

The Brotherhood has shown no signs of backing down. Under the banner of an anti-coup alliance, the group held protests Sunday. In the southern city of Assiut, security forces fired tear gas to disperse hundreds rallying in front of a mosque.

“They think they can end the movement,” said Muslim Brotherhood senior member Saad Emara. “The more killings, the more people join us.”

However, the government blames Islamists for a series of attacks on churches and police stations, increasing public anger against the group.

In his first appearance since the violence began, el-Sissi spoke at length in an hour-long speech about the motives behind ousting Morsi. The general said the Islamist president exploited democracy to monopolize power.

El-Sissi also said Islamists must be included in the country’s politics moving forward. A military timetable calls for the nation’s constitution to be amended and for presidential and parliamentary elections to be held in 2014. El-Sissi’s speech was an attempt to consolidate internal support in the face of international criticism.

Egypt also lost one of the few doves in the country’s military-backed administration Sunday as Mohamed ElBaradei, who resigned as vice president in protest of the use of force against Morsi’s supporters, flew out of Cairo to Vienna.