At least nine Iraqi policemen have been killed in three separate attacks by insurgents in Baghdad and the northern city of Kirkuk on Tuesday.
The restaurant bomb appeared to target policemen having breakfast
Four policemen were shot dead in an ambush east of Kirkuk, while three others were killed and three wounded by a roadside bomb in the centre.
In eastern Baghdad, two policemen were killed and at least six injured by a car bomb planted near a restaurant.
Meanwhile, a professor was shot dead outside his university in Baghdad.
Jasim al-Fidawi taught Arabic literature at Mustansiriya University.
The attack comes a day after another professor and his driver were killed there, a defence ministry official said.
US Marines killed
In the west of Iraq, three US Marines from the 2nd Marine Division were killed on Monday, the US military said.
One marine was killed by a roadside bomb and another was shot dead in Ubaydi, a town close the Syrian border.
The third marine died from wounds he suffered in a bomb attack there on Monday.
The marines had been involved in Operation Steel Curtain, which is aimed at imposing security along the Iraqi-Syrian border.