LUXOR, Egypt — Two people were killed Thursday and their bodies burned in an attack by an Arab family on a rival Nubian clan, sparking fears of wider clashes, an Egyptian security official said.

The official said an Arab family killed the two Nubian men, set the bodies on fire and left them in a donkey cart in the southern city of Aswan. The official spoke on condition of anonymity because he was not authorized to speak to the press.

In April, deadly fighting between the same groups left 26 people dead, with several bodies stacked on donkey carts.

A spokesman for the government-appointed mediation committee, Kamal Takkadom, said Thursday’s killings took place after members of the Nubian family posted humiliating pictures of the previous fighting on Facebook.

The earlier round of violence began after a fight between school students drew in adults. Police said the fight was over the harassment of a girl. Witnesses said offensive graffiti written on the school walls fueled the violence.

Security officials say members of the Arab clan are involved in arms and drugs smuggling. The feud took on a political overtone when the impoverished Arab clan accused the ethnic Nubians of supporting the military, while the Nubians say the Arabs back ousted Islamist President Mohammed Morsi.

Copyright 2014 The Associated Press.