Iran’s Tehran Oil Refinery has suspended all operations, the semi-official Tasnim news agency reported, after a gas leak caused a massive fire sending black plumes of smoke across the city’s skyline.

There were no initial reports of deaths or injuries at the refinery, which is located in southern Tehran and also known as the Tondgouyan oil refinery.

A leak at a liquid gas pipeline at the facility sparked the blaze, state TV said, quoting the Director-General of crisis management for Tehran province, Mansour Darajati, who added that firefighters are at the scene tackling the fire.

The Tehran Oil Refining Co., which runs the refinery, has ruled out sabotage as a cause, the semi-official Iranian Students’ News Agency reported, citing Shaker Khafaei, the company’s head of public relations.

The incident comes on the same day that a fire caused an Iranian navy training ship to sink in the Gulf of Oman and less than two weeks after an explosion at another refinery in Iran’s southwestern, oil-producing region of Abadan.

Darajati said Wednesday’s refinery fire “probably isn’t cause for concern” because of high health and safety standards at the site.