In pictures: Isis destroys Iraq shrines
Images posted on social media appear to show the destruction of about a dozen places of worship across northern Iraq, in areas recently taken over by extremist militants.
Some images showed the al-Qubba Husseiniya, a Shia shrine, being blown up in the city of Mosul.
Militants used a bulldozer to destroy a shrine known as the "Girl's Tomb" in Mosul.
They believe giving special veneration to graves and relics is against the teachings of Islam.
Militants also destroyed the Saad bin Aqeel Husseiniya shrine in Tal Afar, approximately 50 km (35 miles) west of Mosul.
The militants, believed to belong to Isis (Islamic State of Iraq and the Levant), are also reported to have attacked churches in Mosul.
More images showed the Ahmed al-Rifai shrine and tomb in the Mahlabiya district near Tal Afar being attacked with a bulldozer.
The militants have attacked Shia and Sunni shrines alike, and have vowed to continue destroying places of worship which they do not approve of.