Damascus – At least 10 oil field workers were killed Thursday in an attack on their bus in eastern Syria's Deir Ezzor province, state media reported.
"Ten workers at the Al-Kharata oil field were martyred and another was wounded in a terrorist attack on a bus transporting them back from work," the official SANA news agency said, without elaborating.
It was not immediately clear who was responsible.
But the Islamic State group has regularly claimed operations in the oil-rich province that was once a part of its sprawling proto-state straddling Syria and Iraq.
The Syrian Observatory for Human Rights said an explosive device was used in the bus attack in an area of Deir Ezzor where "IS sleeper cells are active".
Al-Kharata oil field lies 20 kilometres (12 miles) southwest of Deir Ezzor city, said the Observatory.
Regime forces recaptured it in 2017 after IS jihadists were expelled from the area, the Observatory said.
The IS group's self-proclaimed caliphate was declared defeated in Syria in the riverside hamlet of Baghouz in March 2019 following a gruelling US-backed offensive.
But the group still attacks government forces from hideouts in the vast Syrian desert, which stretches all the way from the Damascus outskirts to the Iraqi border.
Last month, IS killed at least 13 pro-regime militia fighters in an ambush in Deir Ezzor province, according to the Observatory.
Another five Syrian soldiers were killed in an explosion in Deir Ezzor that same week, state media reported.
The government's ally Russia has carried out heavy air raids on IS positions in the desert over the past two days, the Observatory said.