VATICAN CITY (Reuters) -- Pope Benedict called on political and religious authorities on Sunday to prevent violence against Christians, in an apparent reference to recent attacks on Coptic Christians in Egypt.

"Violence against Christians ... has caused indignation among many people, particularly because it has taken place on the most sacred days of the Christian tradition," Benedict said after his weekly Angelus blessing in Rome.

Six Coptic Christians were killed in drive-by shootings in the town of Nagaa Hamady in southern Egypt on January 6, just before midnight on Coptic Christmas Eve.

Three days later Muslims and Christians set fire to each others' homes and shops in nearby villages, injuring six people, as tension remained high in the area, 60 km (40 miles) north of the tourist and archaeological center Luxor.

"It is necessary that both political and religious authorities do not fail to live up to their responsibilities," the pope said. "We cannot have violence in the name of God."