BELGRADE (Reuters) - A series of explosions badly damaged an ammunition warehouse in the central Serbian town of Cacak Monday, but there were believed to be no casualties, a government official said. The warehouse is part of the Sloboda plant which produces home appliances, but also artillery ammunition, propellants and explosives. Predrag Maric, head of the interior ministrys emergencies department, said the first explosion took place at 1545 GMT and was followed by a series of secondary blasts. A warehouse with explosive ordnance went off, it is separated from the main production facility but we cannot give details about casualties, Maric said. Normally, there should be no workers around that storage facility. The Sloboda plant was badly damaged in 1999 by NATOs bombing campaign against Serbia. The Serbian arms industry has recovered in recent years and exports artillery ammunition to Asian countries and the West, including some NATO members. A similar blast killed three Sloboda workers in 2003 and two were injured in smaller incidents earlier this year. It was the third major explosion to hit Serbian ammunition dumps and ordnance factories in recent years. Four years ago an ammunition warehouse in central Serbia exploded and in 2009 a blast in an ammunition factory in west Serbia killed six people.