TEHRAN, (Reuters) – Up to 10 Iranian workers died on Saturday in hospital after being badly burnt in an explosion in a gas pipeline, the semi-official Fars news agency reported.

The pipeline transporting gas from the Khangiran refinery in Sarakhs to the city of Mashhad in Iran’s northeastern province of Khorasan-e Razavi exploded on Friday when it was accidentally struck by an excavating machine, state media reported.

“About nine to 10 people were killed in the Sarakhs pipeline blast,” Alireza Gharibi, director of Iran Gas Engineering and Development Company, told the semi-official Fars news agency.

Iran’s state television said 50 people also were injured.

The explosion set off a fire covering 2 sq km (.77 sq mile) but it was brought under control, the official IRNA news agency reported.

Iranian Deputy Oil Minister Javad Oji told Fars that gas transfer through the damaged Sarakhs-Mashhad pipeline will be resumed within the next 24-to-36 hours.

Iran is the world’s fourth-largest oil producer and also sits on the world’s second largest natural gas reserves and the country’s economy is heavily dependent on oil and gas revenues.