At least six people were killed and several injured on Saturday when a fire broke out after an explosion at an oxygen plant in southeastern Bangladesh, officials said. The death toll could rise as a rescue operation was ongoing at the plant at Sitakunda, 40km (25 miles) from the south-eastern port city of Chittagong, they added. It was not immediately clear what caused the explosion, a fire service official said. “Six bodies were recovered from the site,” local government official Shahadat Hossain told Reuters, adding that the rescue operation was continuing. A huge bang was heard which shook an area with a radius of up to 2km, police official Nayhanul Bari said, quoting witnesses. A massive fire at a container depot in the area killed 50 people and injured nearly 200 in June last year.