A suicide bomber killed 67 people on Saturday as they left a mosque, shortly after the prime minister urged Iraqis not to lose faith if a U.S. military pull-back sparked more violence, Reuters reported.
lmost all U.S. soldiers will leave urban centers by June 30 under a bilateral security pact signed last year and the entire force that invaded the country in 2003 must be gone by 2012.
Saturday's attack was the deadliest in more than a year.
"Don't lose heart if a breach of security occurs here or there," Nuri al-Maliki told leaders from the ethnic Turkmen community, reiterating a warning that insurgents were likely to take advantage of the U.S. pull-back to launch more attacks.
Analysts warn there may also be a spike in violence by mainly Sunni Islamist insurgents, including al Qaeda, and other violent groups ahead of a parliamentary election next January.
Hours after Maliki spoke, a suicide bomber detonated a truck filled with explosives as crowds of worshippers left a Shi'ite Muslim mosque near Kirkuk, a northern city contested by Arabs, Turkmen and Kurds that sits over vast oil reserves.
Sixty-seven people died, including women and children, and more than 200 were wounded as about 30 homes made of clay bricks disintegrated in the blast zone around the al-Rasul mosque in Taza, said Kirkuk governor Abdul Rahman Mustafa.
"This is a catastrophe for Kirkuk province and especially the town of Taza," Mustafa said.
It was the worst bombing in Iraq since 68 people were killed in a twin bomb attack in Baghdad in March last year.
Such high death tolls remain stubbornly common in Iraq despite a sharp fall in overall violence. Sixty people were killed by two female suicide bombers outside the Shi'ite Iman Moussa al-Kadhim shrine in Baghdad this April, and 50 died in a suicide bomb blast in a restaurant near Kirkuk in December.
"I was sitting in my house when suddenly a powerful blast shook the ground under me," said Hussain Nashaat, 35, his head wrapped in white bandages. "I found myself covered in blood and ran outside in a daze. My lovely neighborhood was just rubble."
There was chaos at Kirkuk's Azadi Hospital, where sirens wailed as workers rushed blood-splattered civilians into the wards. Outside, security officials brandished assault rifles to stop traffic as pick-up trucks raced through the gates.