Italy on Wednesday said the death of its eighteen citizens in an attack in the southern city of Nasiriya would not deter its commitment in helping form a new Iraqi government.
Eight Iraqis were also killed when a truck, followed by a sedan, barrelled through the Italian military police headquarters' gate, and one of them exploded.
The car was carrying a detonator, but it wasn't clear whether that vehicle, the truck or both were packed with explosives, CNN quoted officials as saying.
Italian officials expect the toll to rise as some people are trapped under the rubble of the building, which was flattened.
"No intimidation will budge us from our willingness to help that country rise up again and rebuild itself with self-government, security and freedom," Italian Prime Minister Silvio Berlusconi said in a statement.
"Pain is at this time a feeling shared by the entire nation. But we also feel pride for the courage and humanity with which our troops... have worked and still work to make the situation tolerable for children, women, the elderly and the weak who live in that martyred region."
Flags were lowered to half-mast across Italy and the Italian senate observed a minute of silence.