The mosque is one of the most important religious sites for Sunni Muslims in Iraq.
Sadr appeals for calm
A defence ministry official said that Friday’s clashes were so intense that precise information was difficult to obtain.
Elsewhere, double suicide blasts ripped through a car market in the northern Iraqi city of Tal Afar. Two suicide bombers, one in a car and the other wearing an explosives vest, killed 22 people and wounded 26.
Police in the regional capital, Mosul, said that Friday’s attack was aimed at civilians in an outdoor market for vehicles.
Tal Afar, close to the Syrian border, is mostly home to Turkish-speaking ethnic Turkmen who are divided between Shia and Sunni Muslim believers.
In other news, the UN said on Wednesday that 3,709 civilians had been killed in Iraq in October, the most in any month since the war began 44 months ago. The figure is likely to be eclipsed in November.
Can Iran and Syria help Iraq?
The UN said citizens were leaving the country at 100,000 a month, and that at least 1.6 million Iraqis have left since the US invaded in March 2003.
The International Organisation for Migration, a UN-associated group, said on Tuesday that the number of Iraqis displaced by violence since the Samarra bombing in February 2006 has now increased to almost 250,000 in the 15 central and southern governorates, with more than 1,000 people on average being displaced a day in September, October and November.