A US air strike destroyed two large buildings south of the Iraqi capital used to make and store explosives. "Ground forces called in for air support when they found large amounts of chemicals and improvised-explosive-device making materials in two buildings," in the town of Arab Jubur, south of Baghdad, the military said today. The air strike caused no casualties, it said.Since the launch of a massive security operation in Baghdad in February, Iraqi and US troops have reduced execution-style killings in the capital, but car bombings carried out by suspected Sunni militants remain a major headache. In a bid to stop the flow of explosives into the city, the military is now focusing on detecting bomb-making facilities, which are believed to be largely located on the outskirts of Baghdad.