Gunmen have opened fire on two Sunni mosques in western Baghdad, according to police.
Armed men in two cars sprayed gunfire at the Muhammad Rassulluallah mosque shattering windows and damaging walls.
An hour later gunmen stormed the nearby Ashra al-Mubashara mosque, fleeing when police arrived, say officials.
Elsewhere, at least three people were killed and 15 others injured by a car bomb near a petrol station in the northern city of Kirkuk, police said.
Earlier, the US military confirmed three of their marines died in clashes with insurgents on Thursday in the western province of Anbar.
The US military said they died in clashes in what is a known Sunni-dominated troublespot.
A statement said the three marines were attached to the Army's 1st Armoured Division, which operates in Ramadi, but gave no further details.
Sectarian violence has escalated in Iraq in recent months, with attacks from both Sunni radicals and Shia militias, resulting in the death of thousands of members of both sects, according to Iraqi officials.
In other incidents:
- Six labourers were wounded by a bomb blast in Tayaran Square, Baghdad
- Three police were also wounded in a roadside bomb attack in northern Baghdad
- A Sunni cleric, from a tribe opposed to al-Qaeda was killed while driving in Samarra
- Iraq's national soccer coach has resigned after receiving a death threat.