More than 130 Iraqis -- most of them Sunni Muslims -- have been killed in two days of sectarian violence following Wednesday's bombing of a Shi'ite Muslim shrine.
Dozens of Sunni mosques have been attacked, and some Sunni clerics kidnapped and killed since the bombing of the Shi'ite Askariya shrine in Samarra.
Police outside Baghdad found the remains of 47 people who had been shot to death, while dozens of other bodies were found in and around Baghdad overnight.
Near Samarra, gunmen killed three journalists from the Dubai-based Al Arabiya television network who had reported from the scene of the shrine attack.
The State Department and the media rights group, Reporters Without Borders, condemned the killings. In the southern city of Basra, gunmen dressed in police uniforms raided a prison and killed 11 Sunni detainees. A bomb Thursday in Baquba killed 16 people.
The U.S. military also announced that bomb blasts Wednesday in northern Iraq killed seven American troops. A major Sunni political alliance boycotted a multi-party meeting with President Jalal Talabani to discuss the wave of deadly unrest.
As sectarian violence flared, authorities placed security forces on high alert and extended curfew hours in Baghdad and several other cities.
The Askariya shrine draws pilgrims from around the world. It contains the tombs of the 10th and 11th Shi'ite imams, Ali al-Hadi and his son, Hassan al-Askari. It was built at the site where the 12th Shi'ite imam, Mohammed al-Mahdi, disappeared.
Known as the "hidden iman," he is the son and grandson of the two imams buried at Askariya.
Information for this report is provided by AP, AFP and Reuters.