At least 30 fighters and civilian oil workers were killed when the US-led coalition against the Islamic State group carried out an airstrike against a Syrian oil refinery. The Syrian Observatory for Human Rights said that the strike hit a refinery on the western outskirts of Tel Abyad, on Syria’s border with Turkey.

Trade in oil from small refineries in areas under its control has reportedly been one of the Islamic State’s main sources of funding. The International Energy Agency in October estimated that the US-led air campaign has cut production in areas under Islamic State control from 70,000 to 20,000 barrels per day.

Observatory director Rami Abdel-Rahman said he was not yet able to confirm how many of those killed in the Tel Abyad strike were Islamic State fighters and how many were civilians.

Other airstrikes were reported on Islamic State positions west of the town, amid clashes between the extremists and Kurdish forces who are trying to advance from their enclave around Kobane.

The Kurds say they have now recaptured most of the self-declared autonomous canton of Kobane, after intensive coalition airstrikes helped them push back a major Islamic State assault, which began in September.

The Observatory said five Western deserters from Islamic State were killed in a shootout in northern Syria as they tried to escape towards the Turkish border.

Another five deserters, mostly Western, were captured and four of the group’s fighters who had sought to stop them were killed, the monitoring group said.

Syrian al-Qaeda affiliate the al-Nusra Front and other rebels meanwhile scored a success against Syrian regime forces, pushing them out of the strategic village of Handarat, north of Aleppo, the Observatory said.

Government forces took Handarat five months ago, bringing them closer to encircling rebels holding out in the bomb-shattered eastern sector of the city.

Government barrel bomb attacks and shelling meanwhile killed seven civilians, including two children, in Talbiseh, north of the central Syrian city of Homs, the Observatory said.

In neighbouring Iraq, desertions were also reported in the ranks of Islamic State as government forces and Shiite militias pressed their offensive towards the mainly Sunni city of Tikrit.

Residents in the Hawija area north-east of Tikrit said that Islamic State fighters executed 30 fellow militants who had tried to escape the fighting around Tikrit.

The locals said that the group had posted a special force south of Hawija to intercept and execute deserters.

Officials said government forces were continuing their advance towards Tikrit on the eighth day of their offensive.

Troops were moving in on the centre of al-Alam, north of Tikrit on the opposite bank of the Tigris river, from three directions, military officials said, speaking on condition of anonymity. SAPA