Sharif blamed the attack on the so-called Islamic State of Iraq, an alliance of Sunni groups that includes al-Qaeda in Iraq and has a strong presence in the province.
Qara Lus is a small community of minority Failis, or Kurdish Shias.
US soldiers killed
Also on Saturday, the US military in Iraq announced that eight US soldiers had been killed in the last 48 hours.
Three soldiers were killed on Friday when their vehicle was bit by a bomb northeast of Baghdad, and two more in an ambush inside the city when a man opened fire on a patrol.
|The security surge has left more US troops|
exposed to danger across the country [AP]
Another soldier died in combat in western Iraq, one was shot dead while on foot patrol in Baghdad, and the eighth was killed on Saturday by a roadside bomb south of the capital.
Meanwhile, the US military continued its search for three soldiers who have been missing south of Baghdad since May 12.
Nine people were taken into custody in the town of Amiriya following "tips and information leads", a US military spokesman said.
Two other people "associated" with al-Qaeda were arrested in Baquba, he said.
'Mass grave found'
In other developments, Al Jazeera quoted the mainly Sunni Association of Muslim Scholars in Iraq as saying that US and Iraqi forces had found a mass grave in the Sadiq Amin Mosque in Mahmoudiya, south of Baghdad.
The AMS said in a statement that the Mahdi Army militia of Shia leader Moqtada al-Sadr had seized the mosque several months ago and turned it into a "den for torture and murder of innocent people after kidnapping them".
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In Diwaniya, 180km south of Baghdad, police said that an Iraqi soldier was killed and five civilians were injured in clashes between joint US-Iraqi forces and armed militias.
In Mandali, a town in Baquba, northeast of Baghdad, 15 Iraqis were killed after being abducted by armed men in security forces' uniforms, Al Jazeera said quoting Iraqi security sources.
Iraqi police also said they found 25 bodies in different parts of the capital.
In Tikrit, medical sources said US forces handed over at the city's hospital bodies of seven people killed during clashes in Samarra, Al Jazeera said.
In Samarra, a curfew imposed by the US and Iraqi forces remained in place for the 15th consecutive day on Saturday. Concrete barriers have been erected on the main streets of the city.
In Huwayjah, north of Baghdad, US forces handed over the bodies of four farmers killed during clashes near their farm in Kirkuk, Al Jazeera reported.
|Normal life goes on in Baghdad in the|
constant shadow of violence [AFP]
Separately, Al Jazeera said Hamas al-Iraq, an anti-government group, had released video footage of an explosion purportedly set off by the group's "Islamic Fatah Brigades", targeting a US military vehicle.
Al Jazeera could not confirm the authenticity of the tape from an independent source.
Meanwhile, a statement from the British army in the southern Iraqi city of Basra announced the arrest of Sheikh Aous al-Khafaji, director of the office of the Martyr al-Sadr organisation in Nasiriya, at Basra airport upon his return from Damascus.
Al Jazeera said the office of Martyr al-Sadr in Basra confirmed the news of the arrest.
Al-Khafaji had been released a few months ago after being detained for almost a year and a half by British forces.