Egypt's army rulers imposed a curfew on Cairo's Tahrir Square and downtown area, state media announced on Sunday, after 24 people were reported killed in clashes between Christians and military police in the centre of the capital.
The curfew would last from 2am to 7am local time on Monday, state TV reported.
The Egyptian cabinet called an emergency meeting for Monday, vowing
the violence would not derail the country's first election since Hosni Mubarak was toppled.
The cabinet said in a statement that it would "not let any group manipulate the issue of national unity in Egypt or delay the process of democratic transformation" which it said would begin with opening the doors to candidate nominations.
Cabinet spokesman Mohamed Hegazy told Reuters the cabinet would hold a special session on Monday to discuss the events.
"The most important thing is to contain the situation, see the way forward and the necessary measures to avoid any ramifications," Hegazy said, adding a committee of prominent figures from the church and Al-Azhar mosque would also meet.
Presidential candidate Amr Moussa and political groups said they would hold an emergency meeting on Monday to discuss the violence.
Fighting started when Christians protesting against an attack on a church clashed with military police, witnesses and security sources said. The fighting spread across the downtown area on Sunday.
Protesters threw rocks and petrol bombs at police, and set fire to vehicles as thick smoke wafted through the street, witnesses said, in some of the most violent scenes since an uprising overthrew former President Hosni Mubarak in February.
The clashes took place in Cairos Tahrir Square, the epicenter of the February uprising that overthrew Mubarak.
The clashes began when some protesters threw stones at army troops guarding the television building. Several cars and buses were set on fire.
Hundreds, mostly Christian, were demonstrating in protest at the destruction of a church in the southern Egyptian province of Aswan.
Christians account for around 10 per cent of Egypt's 80-million-strong population. Tensions are not uncommon between them and the country's Muslim majority.
In March, 13 people were killed in sectarian clashes around the Cairo neighborhood of Manshiyet Nasser, shortly after a church was torched in the village of Sol, south of the capital.