Egypt's government has announced a series of security measures to curb religious violence after 12 people died in clashes in the Cairo suburb of Imbaba, sparked by rumours that Christians had abducted a woman who converted to Islam.
The country's army also pledged on Sunday that 190 people would be tried in military courts over Saturday's violence.
The fighting was Egypt's worst interfaith strife since 13 people died on March 9 after a church was burned, and poses a new challenge for generals ruling the country since the ousting of former president Hosni Mubarak in February.
Tension was high and the army cordoned off streets near the Saint Mina church, where about 500 ultraconservative Salafi Muslims had massed on Saturday to call on Christians to hand over the kidnapped woman.
Violence had broken out as more people converged on the church on Saturday. Both sides traded gunfire, firebombs and stones, witnesses said.
Soldiers and police fired shots in the air and used tear gas to separate the sides but stone-throwing went on into the night.
A power cut plunged the neighbourhood into darkness, making it harder for the security forces to quell the violence.
"The Salafis are being blamed, but who exactly is responsible is not clear," Al Jazeera's Rawya Rageh said from Cairo.
"The violence is symptomatic of a bigger problem. In fact, it's about increasing lawlessness in the country since the revolution, and the perception that security forces are being quite lax - not just in dealing with petty crime but with sectarian tension."
Later on Sunday, hundreds of young Christian men ran through central Cairo towards the main state television building calling for the removal of Mohamed Hussein Tantawi, who leads the military council ruling Egypt.
A crowd of Muslim men met them and some sought to calm the Christians' anger but fights broke out and the two groups pelted each other with stones.