Muslims and Christians set fire to each others' homes and shops near the southern Egyptian town of Nagaa Hamady today, three days after a gunman killed six Coptic Christians in a drive-by shooting, security sources said.

"Four houses and a shop belonging to Christians in the village of Tiraks were set on fire by Muslims, while four shops owned by Muslims in the village of al-Bahgorah were set on fire by Christians," a security source said. The villages are near Nagaa Hamady.

Six people, Christian and Muslim, were injured in the fires, they added.

Police have taken 46 statements from Muslims and Christians in the area accusing members of the other faith of attacking their houses and damaging their properties, the sources said.

The drive-by shootings in Nagaa Hamady took place around midnight on Coptic Christmas Eve on Wednesday night. Muslim and Christian groups held separate protests on Thursday and yesterday.

The source said police had detained about 25 of the 2,000 protesters.

Security sources named three Muslims, who have since surrendered to police, as the suspected gunmen. They first fired on a crowd in a shopping area near a church in Nagaa Hamady, killing two Christians.

They then went to the nearby church and shot five more, including the church's Muslim guard. Another nine Christians were wounded.

Police investigators in the city 60 km north of the tourist and archaeological centre of Luxor, said two of the three assailants were distantly related to a Muslim girl allegedly raped by a Christian more than a month earlier.

Egypt's government said the violence was not sectarian and was an isolated incident.

Christians account for about 10 percent of Egypt's predominantly Muslim population of about 78 million. Sectarian violence is rare, but disputes over issues including land or women occasionally erupt.