At least six Coptic Christians and a security official have been killed in a drive-by shooting outside a church in southern Egypt, officials say.
The shooting came as worshippers left the church in Naj Hammadi after a midnight mass on Coptic Christmas Eve.
A car pulled up and gunfire was sprayed into the crowd.
Officials say they suspect the attack is in revenge for the rape of a 12-year-old Muslim girl by a Christian man in the town in November.
There were five days of riots in the town, with Christian properties torched and damaged, following the rape.
Police said the chief attacker in Wednesday's shooting had been identified but no arrests had yet been made.
Tensions in the area are said to be high, with reports of clashes.
The BBC's Yolande Knell, in Cairo
Since the 1970s, when Islamic extremism began to increase in Egypt, there have been sporadic clashes between Muslims and members of the Coptic Christian minority.
The most serious cases are usually in poor, rural areas where the trigger is often a dispute over land or women, which spills over into sectarian violence. Whole communities can become involved.
Local authorities' handling of such cases is often criticised. Police are accused of delaying their response to reports of fighting and then simply arresting equal numbers of individuals from each faith. Sometimes criminal investigations are dropped in favour of informal reconciliation meetings.
The church's Bishop Kirollos said there had been threats in the days leading up to the Christmas Eve service - a reason he decided to end his mass an hour earlier than normal.
"For days, I had expected something to happen on Christmas Eve," he told the Associated Press.
He said he left the church minutes before the attack.
"A driving car swerved near me, so I took the back door," he said. "By the time I shook hands with someone at the gate, I heard the mayhem, lots of machine-gun shots."
Two Muslim passers-by were among 10 people reportedly injured in the attack.
Naj Hammadi is 40 miles (64km) from Luxor, southern Egypt's biggest city.
Coptic Christians - who make up 10% of Egypt's 80 million population - have complained of harassment and discrimination.
Some Copts argue that previous attacks on them have gone unpunished or have drawn light sentences.
Most Christians in Egypt are Copts - Christians descended from the ancient Egyptians.
Their church split from the Eastern Orthodox and Roman Catholic churches in 451AD because of a theological dispute over the nature of Christ, but is now, on most issues, doctrinally similar to the Eastern Orthodox church.