Thousands clashed with police during a funeral procession Thursday for six of seven people killed in an attack on churchgoers leaving a midnight Mass for Coptic Christians, security officials said.
Throughout the day, protesters in the southern town of Nag Hamadi pelted police with rocks and damaged cars and stores.
Early in the day, they smashed ambulances outside a hospital in frustration over delays in turning over the bodies for burial. A security official said police fired tear gas to disperse the crowd.
The riots resumed after the burial services, with angry Copts smashing shop windows, chasing Muslims off the streets and bringing down street light poles. The riots continued into the late afternoon.
The official and witnesses spoke on condition of anonymity because of the sensitivity of the issue.
The riots followed an attack the previous night, in which three gunmen in a car sprayed automatic gunfire into a crowd leaving a church in Nag Hamadi, about 40 miles north of the ancient ruins of Luxor.
The lead attacker was identified by authorities as a known criminal.
Christians, mostly Copts, account for about 10 percent of Egypt's predominantly Muslim population of some 80 million people. They generally live in peace with Muslims although clashes and tensions occasionally occur in southern Egypt, mostly over land or church construction disputes.
In recent years, the clashes have spread to the capital.
Wednesday's attack, which happened on the holiest day in the Coptic calendar, was the worst known incident of sectarian violence in a decade.
In 2000, the deadliest Christian-Muslim clashes in years left 23 people dead. All but two of the 23 were Copts. The clashes were touched off by an argument between a Coptic merchant and a Muslim shopper in the southern village of el-Kusheh.
The latest attack, however, was unusual because it appeared to have been planned, rather than the customary spontaneous violence that arises from misunderstandings or disputes between Muslims and Copts.
Egypt's Interior Ministry said it suspected that Wednesday's attack was in retaliation for the alleged November rape of a Muslim girl by a Christian man in the same town. The man is in custody awaiting trial.
Security was tight in the town Thursday as police searched for suspects. The release of bodies may have been delayed because of fear the funerals would turn into a flashpoint for more violence.
The funeral procession took place later and was attended by local officials. The security officials said some 5,000 protesters shouted: "Long live the Cross," and "No to persecution." The protesters also stoned police cars, and scuffled with security. Shops shut their doors in the town to avoid the violence.
The Bishop of the Nag Hamadi Diocese said the dead were mostly young males in their teens.
As Islamic conservatism gains ground, Egypt's Christians have increasingly complained about discrimination by the Muslim majority.
Coptic Christians are limited in where they can build churches and must obtain government approval before expanding existing facilities. The government insists Christians enjoy the same rights as Muslims.
The head of provincial security, Mahmoud Gohar, said security was beefed up in the town and neighboring villages, and checkpoints were set up in the area as tensions ran high among the town's Christian population. Gohar said an angry crowd from a nearby church smashed two police cars shortly after the attack.
The attack, he said, happened in the town's main street about 200 meters (yards) from the church. He said nine people were injured in the attack, including three who were in critical condition.
Bishop Kirollos of the Nag Hamadi Diocese told The Associated Press six male churchgoers and one security guard were killed. He said he left St. John's church for his nearby home just minutes before the attack. He said he saw five bodies lying on the ground.
"I heard the mayhem, lots of machine gun shots," he said in a telephone interview.
The bishop said he was concerned about violence on the eve of the Coptic Christmas, which falls Thursday, because of previous threats following the alleged rape of the 12-year-old Muslim girl in November.
He recently received a message on his mobile phone that said: "It is your turn," he said.
"My faithful were also receiving threats in the streets, some shouting at them: 'We will not let you have festivities,'" he said.
Because of the threats, he said he ended his Christmas Mass one hour early.
He said Muslim residents of Nag Hamadi and neighboring villages rioted for five days in November and torched and damaged Christian properties in the area after the rape.
"For days, I had expected something to happen on Christmas Day," he said. The bishop said police have asked him to stay at home for fear of further violence.
Qena, in which Nag Hamadi is located, is one of Egypt's poorest and most conservative areas.
A recent Amnesty International report said attacks on the Coptic Christian community, comprising between 6 million and 8 million people in Egypt, increased in the year 2008, leaving eight people dead.
The bishop said the attack could have been motivated by revenge and blamed it on "Muslim radicals."
"Suppose it is vengeance, where was the security?" he asked.
"We are facing a religious war and lax security."