The source, who declined to be named, said the decision to bring forward the September start date of the partial troop reduction was logistical and financial – and not political.

The 130 Marines had finished their roughly 4-month tour-of-duty earlier in August, and the military opted against a costly process of replacing them for a brief one-month stint.

"It was decided not to replace them just for one month, since the reduction of around 300 men was planned starting in September," the source said.

Italy has some 3,000 troops in Iraq, the fourth largest foreign contingent there after the United States, Britain and South Korea.

Prime Minister Silvio Berlusconi last month insisted he would not speed the withdrawal from Iraq, despite calls to speed the process – even from allies within his government – following the deadly bomb attacks in London.

The strong US ally said Italy needed to fulfil its commitments and refused to "leave the job half done".