|A dozen people have been killed in the clashes that have occurred in the Cairo district of Imbaba
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.
Saturday's attack was the latest sign of assertiveness by the Salafists, whose increasing hostility towards Egypt's Coptic Christians has met with little interference from the country's military rulers.
Some Christians said security forces had been too slow to disperse the crowd in front of Saint Mina and looked on as the tension got out of hand.
Essam Sharaf, Egypt's prime minister, cancelled a tour of Gulf Arab states to chair a cabinet meeting where the government decided to deploy more security near religious sites and toughen laws criminalising attacks on places of worship.
"Gatherings around places of worship will be banned to protect their sanctity and ensure the security of residents and prevent sectarian strife," Mohamed el-Guindy, the justice minister, said in a statement read on state television.
The governor of Giza province, where the targeted church is situated, said relatives of the dead and injured would receive financial compensation.
"I think the army is in a state of confusion," Gamal Eid, a prominent author and human rights activist, said.
"It is afraid to take serious action against extremists so as not to be accused of suppressing these movements."
Peter el-Naggar, a Christian lawyer, blamed the clashes on Salafists seeking the support of more moderate Muslims.
"They want to gain the sympathy of the Egyptian Muslims and they think that by doing what they are doing, they would reach this goal and gain political ground," he said.
Sectarian strife often flares in Egypt over conversions, family disputes and the construction of churches.
Muslims and Christians made demonstrations of unity during the protests that overthrew Mubarak, but interfaith tensions have grown.
Hundreds of people gathered in Alexandria on Sunday to call for religious unity and punishment for those who took part in Saturday's violence.
"They must strike with an iron fist against anyone who has killed an Egyptian, regardless of their religion or political orientation," Mina Gergis, a 22-year-old college student, said.
Al-Azhar, Egypt's highest religious authority, held an emergency meeting to discuss the clashes, and the Grand Mufti called for a conference of national reconciliation.
In one of the worst attacks against Coptic Christians, a suicide bomber killed 21 people outside a church in the port city of Alexandria on January 1, setting off days of protests.
Egypt made some arrests but never charged anyone with the attack.
"The government didn't apply the law over the past few decades," Sameh Fawzi, an Egyptian columnist, said.
"But now I would like to see the government take over and sustain sovereignty in Egyptian society."
Tensions have been building for the past year, as Salafists protested the alleged abduction by the Coptic Church of a priest's wife, Camilla Shehata.
The Salafists claim she converted to Islam to escape an unhappy marriage, a phenomenon they maintain is common.
Because divorce is banned under the Coptic Church, with rare exceptions such as conversion, some Christian women resort to conversion to Islam or another Christian denomination to get out of a marriage.
Shehata's case was used by the Iraqi branch of al-Qaeda as a justification for an attack on a Baghdad church that killed 68 people.
On Saturday, just before the violence erupted in Imbaba, Shehata appeared with her husband and child on a Christian TV station broadcast from outside of Egypt and asserted that she was still a Christian and had never converted.
"Let the protesters leave the church alone and turn their attention to Egypt's future," she said from an undisclosed location.