Two Italian soldiers were killed and two others were seriously injured on Monday when a bomb hit a NATO military convoy in northwestern Afghanistan, Italy's foreign ministry told AFP. The four were in a vehicle that was struck by a roadside bomb. Italy's Prime Minister Silvio Berlusconi expressed his condolences for the deaths but underscored his commitment to keeping troops in Afghanistan. "The mission in Afghanistan to stabilise and pacify a strategic region is of fundamental importance" he said in a statement. The lives of the injured were not in danger. The attack was about 25 kilometres (15.5 miles) south of the town of Bala Murghab on the border with Turkmenistan, a spokesman for the Italian contingent in Afghanistan said in a television interview. Italy has 3,300 troops in Afghanistan as part of NATO's International Security Assistance Force and heads the western regional command headquartered in the city of Herat.