Airstrikes hit ISIL bases in Syria for third night

Air and missile strikes, believed to be carried out by U.S.-led forces, hit oil fields and Islamic State in Iraq and the Levant (ISIL) bases for a third time in eastern Syria overnight and early Friday, a monitoring group said.

U.S. and Arab forces started bombing ISIL in northern and eastern Syria on Tuesday. The U.S. has been bombing bases of the Al-Qaeda splinter group in Iraq since last month.

The air raids follow growing alarm in Western and Arab capitals after ISIL swept through a swath of Iraq in June, proclaimed a "caliphate," slaughtered prisoners and ordered Shia and non-Muslims to convert or die.

The airstrikes early on Friday hit ISIL bases and positions on the outskirts of the city of al-Mayadin in Deir al-Zor province, said the Britain-based Syrian Observatory for Human Rights, which monitors Syria's civil war through a network of local sources.

An earlier airstrike hit the al-Tanak oil field in the province, while apparent missile strikes – also thought to be carried out by U.S.-led forces – hit the al-Quriyah area, also in Deir al-Zor, the monitoring group said.

At least 14 ISIL fighters and five civilians were killed in those strikes, the Observatory reported.

Strikes also hit areas southeast of the city of Hasaka, close to Syria's border with Iraq. They targeted ISIL, Al-Qaeda's Nusra Front and other armed groups, the Observatory said.

Deir al-Zor, which borders Iraq, is almost entirely controlled by ISIL and was a major oil-producing province before Syria's conflict began more than three years ago.

Oil has been a top source of revenue for ISIL, and air raids on Thursday targeted refineries controlled by the group. The strikes also have seemed to be intended to hamper ISIL's ability to operate across the border with Iraq, where it also controls territory.

Al Jazeera and Reuters