Iraqi militants launched a sustained mortar and grenade attack on the headquarters of the US-led administration in Nassiriya overnight.
About 20 Italian, British and US staff and international journalists took cover inside during the four-hour barrage which ended at around 7 a.m. Irish time.
Ms Andrea Angeli, a spokesman for the Coalition Provisional Authority holed up inside the building, said mortars, rocket-propelled grenades and assault rifle fire rained down through the night.
"There is some damage to the building, but it withstood most of it," she said.
Two Filipino private security guards were wounded as they fought back against the militants, members of Shi'ite Muslim cleric Moqtada al-Sadr's Mehdi Army militia, which has launched an uprising across much of southern Iraq.
Italian troops, who are in charge of security in Nassiriya, evacuated the wounded Filipinos to a military base, and skirmished with militants throughout the town, an Italian military spokesman said.
He said the situation in Nassiriya remained "extremely fluid" and could not say whether Italian forces or Shi'ite militiamen had control of the town. He said no Italian troops had been wounded and had no details about militia casualties.