US and Iraqi troops clashed with gunmen in a town south of Baghdad on Sunday (March 25) shortly after a Sunni mosque was set ablaze in an apparent revenge attack for the destruction of a Shi'ite mosque in the town a day earlier. A Reuters cameraman was pinned down in the fighting in which a column of armoured Humvees came under machinegun fire close to the Shi'ite mosque, where Shi'ite residents had been combing through the debris of the demolished building. US troops could be seen running into buildings nearby. The area was rocked by an explosion that sent a large cloud of dust into the air. The cause of the blast was not immediately clear. Police in Hilla, close to the town of Haswa, where the fighting occurred, said a curfew had been imposed. Gunmen stormed the mosque in Haswa, a religiously mixed town about 50 km (35 miles) south of the Iraqi capital, and destroyed its minaret in a blast. The building was set on fire, a police official said, describing it as an apparent revenge attack. They said at least four people were wounded. A second Sunni mosque was attacked but damage was reported to be minor. There were no casualty figures from the fighting. A suicide truck bomber exploded outside a Shi'ite mosque in Haswa on Saturday (March 24), killing 14 and wounding 21, Hilla police said. The provincial health directorate, while Baghdad police put the toll at 16. Only the mosque's minaret was left standing. Mosques and other religious buildings have been frequent targets of attack. The bombing of a revered Shi'ite shrine, the al-Askariya mosque, in the town of Samarra in February 2006 sparked a wave of sectarian fighting between Iraq's majority Shi'ites and minority Sunnis that has killed tens of thousands.