CAIRO (AP) — Egyptian authorities have detained a Coptic Christian student accused of posting a drawing of Islam’s prophet on Facebook that triggered two days of violence in southern Egypt.

Gamal Massoud has been accused by fellow students of ridiculing the Prophet Muhammad.

According to a security official, the 17-year-old student denies that and says friends posted the picture on his Facebook page. The official spoke Saturday on condition of anonymity because he was not authorized to speak to the press.

Since Wednesday, villagers have attacked Massoud’s house while chanting “Allahu akbar,” or “God is Great.”

They have set fire to other Christians’ houses.

Many Christian villagers fearing retaliation have left their homes.

Security forces intervened, using tear gas to disperse Muslim protesters.