Shafaq News/ An attack in eastern Syria has killed at least 10 oil field workers, state news agency SANA has reported, a day after Syrian Kurdish-led forces announced an offensive against ISIL (IS).

“Two others have been wounded in a terrorist attack that targeted three buses transporting workers from al-Taim oil field in Deir Az Zor” province, the report said on Friday.

SANA did not provide any information on the nature of the attack or who may be behind it, but a British-based war monitor, in reference to ISIL, accused “cells of the Islamic State group” of carrying out the assault near the oil field.

“The attack began with explosive devices that went off as the buses drove by, and then the group’s militants shot at them,” Rami Abdurrahman, director of the Syrian Observatory for Human Rights, told AFP.

On Thursday, the Kurdish-led Syrian Democratic Forces (SDF) said they had begun an offensive against ISIL fighters, following an earlier assault on a prison in Raqqa, northwest of the attack on the bus.

The SDF said the offensive, dubbed “Operation al-Jazeera Thunderbolt”, aimed to “eliminate” ISIL fighters from areas that had been “the source of the recent terrorist attacks”.

The operation is being carried out alongside the US-backed coalition, although there was no immediate confirmation from the international force that they were taking part.

The SDF statement said that in addition to the thwarted Raqqa attack, ISIL fighters had recently carried out eight assaults in the Deir Az Zor area, Hasakah and the al-Hol camp for displaced people, which houses predominantly family members of ISIL members.

Last Monday, six Kurdish fighters were killed when ISIL fighters attacked the complex in Raqqa, the group’s former de facto capital in Syria, in a bid to free fellow fighters imprisoned there.

After a meteoric rise in Iraq and Syria in 2014, ISIL lost the vast swaths of territory under its control, but fighters remain and the group continues to claim attacks in the two countries.

In December, ISIL this month carried out 14 attacks on Syrian government forces and their allies, leaving at least 55 dead, according to the Syrian Observatory