NASSIRIYA, Iraq (Reuters) - Radical Shi'ite militiamen fought gun battles with Italian troops in the southern town of Nassiriya on Tuesday and two civilians were killed, witnesses said. The violence was part of a surge of unrest led by Moqtada al-Sadr, a cleric fiercely opposed to the U.S.-led occupation. The fighting in Nassiriya erupted at about 4 a.m. (0000 GMT) and continued into the morning. Four Italian vehicles had been burned in the clashes in the Zeitoun district, witnesses said. Pro-Sadr fighters were still controlling the area, near the local headquarters of Iraq (news - web sites)'s Coalition Provisional...