BUCHAREST, Romania—An explosion Thursday at a weapons factory in a small southern town in Romania killed four people and injured another four, local media said. The afternoon blast occurred in the town of Babeni in Valcea County about 125 miles from the capital, Bucharest, and was caused by an anti-personnel mine, Romania’s National Press Agency said. It said the victims were three men and a woman. No details were immediately available on the condition of the injured people. The press agency said prosecutors have opened a criminal case and a team of law enforcement specialists have been sent to the site of the explosion to investigate. According to the website of the plant’s parent company, Energotech Group, the factory is a certified supplier for the Romanian ministry of defense and NATO. In 2019, an accidental explosion at the same Babeni factory killed a 22-year-old man.