The explosion appeared timed to come after evening prayers.
Sectarian violence has escalated since a February bombing of an important Shi'ite shrine in Samarra and reprisal attacks against Sunni Muslims.
Reports said 17 other Iraqis were killed today in violent acts around the country.
Also today, the U.S. military said five Marines and were killed in the western Anbar province when their truck rolled over in a flash flood. One Marine was injured, and two Marines and one sailor were missing after the accident.
(Compiled from agency reports)
Iraqi religious and government leaders, as well as international officials, condemned the February 22 bomb attack that wrecked the Golden Mosque, a major Shi'ite Muslim shrine in Samarra. Below is a selection of statements on the incident.
"This new ugly crime comes as a warning that there is a conspiracy against the Iraqi people to spark a war among brothers. God willing, we will not allow this.... We must cooperate and work together against this danger, the danger of civil war. This is the fiercest danger because it threatens our unity and our country with a devastating civil war." -- Iraqi President Jalal Talabani
"The timing of this crime indicates that one of its aims is to stall the political process and to hamper the negotiations on the formation of a national-unity government." -- President Talabani
"I announce on this occasion three days of mourning. I hope our heroic people will take more care on this occasion to bolster Islamic unity and protect Islamic brotherhood and Iraqi national brotherhood." -- Iraqi Prime Minister Ibrahim al-Ja'fari
"Oh honorable people of Samarra! We should stand as one, united in confronting terrorism.... This assault is an assault on all Muslims." -- Iraqi Interior Minister Bayan Jabur
"They will fail to draw the Iraqi people into civil war as they have failed in the past." -- Iraqi National Security Adviser Muwaffaq al-Rubay'i
"If the security systems are unable to secure necessary protection, the believers are able to do so with the might of God." -- Shi'ite spiritual leader Grand Ayatollah Ali al-Sistani
"We will not only condemn and protest but we will act against those militants. If the Iraqi government does not do its job to defend the Iraqi people we are ready to do so." -- Shi'ite cleric Moqtada al-Sadr, speaking through spokesman Abdel Hadi al-Darajee
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