U.N. High Commissioner for Human Rights Navi Pillay said a video depiction of a Syrian rebel leader desecrating the body of a Syrian solider was atrocious.
"Mutilating or desecrating corpses during a conflict is a war crime," she said in a statement.
Pillay said she's "repeatedly" called for the situation in Syria to be referred to the International Criminal Court. She expressed similar outrage over last week's massacres in the coastal Syrian towns of Baida and Banias.
Attacks by Syrian forces were alleged to be an ethnic-cleansing campaign against the Sunni population. The alleged corpse desecration targeted an Alawite, a Shiite group that counts Syrian President Bashar Assad as a member.
Khalid al-Hamad, commander of the rebel Farouq Brigades and alleged perpetrator, told Time magazine his forces hoped to "slaughter" all of the Allawites in Syria. He said he has another video showing him cutting up the body of a member of the pro-government Shabiha militia.
The rebel Free Syrian Army, the largest such group, said Hamad's actions were contrary to the moral values of the Syrian people.