Cairo (CNN) -- At least 23 people were killed Sunday when Egyptian army forces clashed with thousands of people protesting more than a week after the burning of a Coptic Christian church, officials said.
Dr. Sheriff Doss, the head of Egypt's chief association of Coptics, said 17 civilians died and 40 were injured.
In addition, 12 army troops were killed and over 50 were injured, according to Amr Imam, an army spokesman.
Meanwhile, health ministry spokesman Adel Al Dawi said late Sunday that there were a total of 23 people dead and more than 180 injured.
The protesters -- many of them Coptics or supportive of their cause -- said they had been marching peacefully toward the Egyptian state television building, demanding equality and protection of Coptic places of worship.
"Suddenly, we were attacked by thugs carrying swords and clubs," one protester, Magdi Hanna, told CNN.
According to Alla Mahmoud, an interior ministry spokesman, some protesters began "firing live ammunition at the army."
"This is the first time protesters fired at the army," added Imam, the military spokesman. "There must be a hidden hand behind this. Egyptians don't do that."
Military trucks were later seen burning on the street as the clashes continued.
The January 25 youth revolution coalition, which has been involved in various anti-government protests including Sunday's demonstration, denied that any participants shot at the Egyptian forces.
Samir Bolos, one of the demonstrators, added Sunday that "some unknown people may have fired at the army, but not us."
Witnesses said the army forces fired on the protesters near the state television headquarters.
Hundreds of demonstrators also went to Tahrir Square, the hub of the revolutionary movement that led to the ouster of longtime Egyptian President Hosni Mubarak earlier this year, according to Bolos. He claimed military police stormed the square with sticks, while protesters fought back with rocks.
A curfew has been imposed for between 2 a.m. and 7 a.m. Monday around Tahrir Square and central Cairo, state TV reported.
Egypt's National Justice Committee plans to hold an emergency meeting Monday involving representatives from the Supreme Council of the Armed Forces, the al-Azhar mosque and the Coptic church to discuss the developments, prime ministry spokesman Mohamed Hegazy said. Those talks will be held in the prime minister's building.
Also, state TV reported Sunday night that Ahmed al-Tayyeb, a prominent Egyptian Muslim leader and grand imam of Al-Azhar, has been reaching out to Coptic church leaders in hopes of containing the crisis.
The protests and clashes follow the September 30 burning of the Mar Girgis church in Edfu, a city in Aswan governorate in southern Egypt.
That attack marked the latest of several examples in which Coptic Christians have been targeted in the North African nation.
About 9% of Egypt's 80 million residents are Coptic Christians. They base their theology on the teachings of the Apostle Mark, who introduced Christianity to Egypt, according to St. Takla Church in Alexandria, the capital of Coptic Christianity.
The religion split with other Christians in the 5th century over the definition of the divinity of Jesus Christ.
In Egypt, they have been targeted of late, including the New Year's Day bombing of a Coptic church in Alexandria that left 23 people dead. There have also been sectarian clashes, including one in Cairo on May 7 in which at least 12 people were killed.
The U.S. Commission on International Religious Freedom, an independent bipartisan federal agency, earlier this year added Egypt to a list of countries named as the worst violators of religious freedom.
Sunday's incident also marks the latest skirmish between protesters and government forces.
An incident last Tuesday outside a military court in Nasr City resulted in the arrests of two protesters. Journalists covering the demonstration were assaulted, according to witnesses.
The same day, military police fired shots into the air to disperse about 400 pro-Coptic demonstrators who had attempted to stage a sit-in in front of the state television building after marching through the streets of Cairo.