Serbia's defense ministry says a fire has erupted at a munitions factory, injuring four workers, one seriously.

The ministry said in a statement the fire broke out Wednesday morning in Lucani, 270 kilometers (170 miles) southeast of the capital, Belgrade, at a machine producing gun powder. It said the fire had been put out and the injuries were from burns.

The injured men were hospitalized at the nearby town of Cacak.

Serbia has a poor factory safety record, with several explosions and accidents at weapons and munitions plants in recent years, some of them deadly. Only a day earlier, fire on another machine injured two other workers at the same factory in Lucani, Serbian media reported.

The ministry says it has opened an investigation into the fire.