Assad's regime is dominated by members of his minority Alawite sect, an off-shoot of Shiite Islam, while most of the rebels are Sunni Muslims.
Mainly Sunni Islamic extremists have joined the rebels in their fight against Assad, including Jabhat al-Nusra. The U.S. says the group is linked to al-Qaida, and has declared it a terrorist organization.
Human Rights Watch previously documented the destruction and looting of a mosque in the town of Taftanaz in Idlib province by Syrian government forces.
"The destruction of religious sites is furthering sectarian fears and compounding the tragedies of the country, with tens of thousands killed," said Sarah Leah Whitson, Middle East director at Human Rights Watch. "Syria will lose its rich cultural and religious diversity if armed groups do not respect places of worship. Leaders on both sides should send a message that those who attack these sites will be held accountable."
Isachenkov reported from Moscow.
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.