The Jazal field was now shut down and clashes were ongoing east of Homs, with casualties reported on both sides, the Britain-based Syrian Observatory for Human Rights said, without giving dates or more details.

Syria’s army said it had repulsed an attack in the same area but did not mention Jazal or comment on how much of the country’s battered energy infrastructure remained under its sway. It said it killed 25 fighters, including non-Syrian jihadists.

“The regime has lost the last oilfield in Syria,” said the Observatory, which tracks violence through a network of sources on the ground.