It was broad daylight – but judging from the darkened skies in Qayyarah, the Iraqi army could have been forgiven for thinking otherwise as they battled to retake towns and villages near Mosul from ISIL.

Miles of oil pipelines were still ablaze on Thursday, allegedly set alight by the Islamic State group, also known as Daesh.

An American general estimates that between 800 to 900 fighters from the militant group have been killed since the offensive began to regain control of Iraq’s second-largest city and the region around it.

General Joseph Votel, head of the US Central Command (Centcom) who has been visiting US troops in the area, told AFP that it was difficult to provide precise figures as ISIL fighters moved around in small groups, and were trying to melt into the population.

For now the offensive, launched on October 17 on three fronts – the east, north and south – is concentrating on areas surrounding Mosul, according to military authorities.

Progress has been rapid but stronger resistance is expected when Iraqi forces try to penetrate ISIL defence lines and enter the city where the extremists declared a “caliphate” in June 2014.

Iraqi forces have also been fighting off sniper fire and suicide car bombs.

An explosion was seen near Bashiqa mountain close to Mosul on Thursday as operations continued.

Turkey, which has a base there, has reportedly proposed that its forces take part in the coalition against the militants.