At least 23 people were killed and 150 injured Sunday in the Egyptian capital, Cairo, when a protest by Coptic Christians over the recent burning of a church escalated into rioting against military rule.

Protesters used firebombs, set army vehicles alight and battled with security forces in Egypt's most violent clashes since the February uprising that ousted former president Hosni Mubarak.

Hundreds of rioters fought with police, some of them tearing up pavement and using rocks for ammunition. At one point, an armored security van sped into the crowd, crushing some protesters to death. Two soldiers also died in Sunday's clashes.

Christian demonstrators said a peaceful rally in the mostly Coptic neighborhood of Shubra turned deadly when the group marched to Egypt's Radio and Television Building where plainclothes police attacked them. The protests later spread to Tahrir Square, the focal point of the February revolution.

State media reported that Egypt's interim Cabinet is holding an emergency session to discuss the situation. The army imposed a nighttime curfew on Tahrir Square and the surrounding area .

In the past few weeks, riots have broken out at two churches in southern Egypt, prompted by Muslim crowds angry about church construction.

One clash took place near the city of Aswan after church officials agreed to a demand by local ultra-conservative Muslims – known as Salafis – that a cross and bells be removed from the church building.

Aswan's governor, Mustafa Kamel al-Sayyed, is also reported to have suggested that the church does not have legal authorization. Protesters said Sunday they are demanding the governor's ouster after the church was burned and partially demolished last week.

Christians make up about one-tenth of Egypt's 80 million people and often face attacks from Islamic extremists. Copts joined with Muslims during the protests that ousted Mr. Mubarak, but sectarian troubles have since intensified.

Egypt has been considering new laws designed to stem sectarian violence, including banning protests at places of worship and the use of religious slogans to incite hatred.

In May, 12 people were killed in sectarian clashes between Christians and Muslims after rumors spread that Christians were holding a woman who had converted to Islam.