The death toll from two days of clashes between supporters and opponents of Egypt’s ousted president rose to 11 on Tuesday, most of them killed in pre-dawn street battles near a pro-Mohamed Morsi protest camp as the country remained mired in deadly turmoil three weeks after the military overthrew the Islamist leader.

Early Wednesday, a bomb blast outside the security headquarters in Mansoura, capital of the Nile Delta province of Dakahliya, wounded 19 people, security officials said.

The bloodshed is widening the divisions between Morsi’s supporters and the military-backed administration that took over after he was toppled and diminishing the chances of reconciliation. Fueling the anger is the continued detention of Morsi, the country’s first freely elected president, who has been held incommunicado and without charge.

Violence has repeatedly broken out amid rival demonstrations by the two sides, but the running street battles that began before dawn Tuesday were among the most intense since the crisis began July 3.

Clashes erupted after Morsi supporters began marching from their sit-in outside the main campus of Cairo University to a nearby mosque. The protesters blocked roads, causing traffic jams and angering residents.

Security officials said the fighting turned deadly after masked gunmen appeared at the scene and started shooting at Morsi supporters with live ammunition and birdshot. The officials, who spoke on the condition of anonymity because they were not authorized to release the information, had no word on the identity of the gunmen.

The Muslim Brotherhood, however, blamed the killings on “thugs” sponsored by the Interior Ministry, a charge that the Islamist group that supports Morsi often uses to dismiss the notion that it was at odds with other segments of the population.

Khaled el-Khateeb, who heads the Health Ministry’s emergency and intensive care department, said six people were killed near the pro-Morsi sit-in. Security officials put the casualty toll at seven killed and 11 injured.

The ouster of Morsi followed street protests by millions of Egyptians demanding that the Islamist president step down. His supporters are calling for his reinstatement.

Clashes also broke out Monday, leaving three people dead in the town of Qalioub, north of Cairo. Backers of the two sides also fought near the site of another pro-Morsi protest camp in an eastern Cairo district and in the central Tahrir Square, birthplace of the 2011 uprising that toppled Morsi’s authoritarian predecessor, Hosni Mubarak.

At least one person was killed near Tahrir, officials said.

— Associated Press