Three Sunni Muslim mosques were attacked and burned south of Baghdad today.
The burnings were apparent reprisal attacks after militants blew up the minarets of a revered Shia shrine yesterday.
Tens of thousands of Iraqi and US soldiers were on the streets of Baghdad and other cities enforcing curfews imposed after the bombing at Samarra's al-Askari mosque toppled its two golden minarets.
However, s everal mortar rounds landed inside the city's heavily fortified Green Zone. Puffs of white smoke could be seen rising from the centre of the zone near Iraq's parliament building, convention centre and the US military's media unit. The zone is home to several government ministries and the US and British embassies.
A British embassy spokeswoman would not comment on the strikes.
An attack on the same mosque in February 2006 unleashed waves of sectarian violence in which tens of thousands of people were killed, tipping Iraq close to all-out civil war between majority Shias and minority Sunni Arabs.
Police said unidentified gunmen today attacked the al-Mustafa and Huteen mosques in the town of Iskandariya, where the Sunni Grand Mosque was destroyed yesterday. The al-Bashir mosque in nearby Mahaweel was also attacked.
The streets of Baghdad rang with gunfire overnight as gunmen attempted to attack a major Sunni mosque in the centre of the city, residents said.
The mosque attacks south of Baghdad happened a day before US commanders have said all US troop reinforcements would be in place as part of a security crackdown in the capital involving 28,000 extra US soldiers.
The crackdown is aimed at securing the capital so Iraqi Prime Minister Nuri al-Maliki's government can reach political targets set by Washington aimed at promoting national reconciliation.