The Islamic State (Isis) is being beaten in the battle for Iraq's second city, Mosul, a spokesman for the US-led coalition has declared.

The Iraqi army resumed the offensive against the terrorist organisation on Sunday (26 March) after a lull in fighting sparked by public fury over a rising civilian death toll. The US-led coalition has faced growing public anger after an air strike in west Mosul on 17 March killed as many as 200 civilians.

"Right now, the offensive is going very well," Brig Gen Matthew Isler, a deputy commanding general for the US-led coalition, told Sky News.

"The Iraqi security forces are making continuous progress and Daesh [an Arabic acronym for Isis or Islamic State] is fighting very hard to resist but they are unable to deny the Iraqi security forces their objectives.

"So we are witnessing the defeat of Daesh," Isler added.

While it is difficult to independently confirm the number of people who died in the air strike in the al-Jadida district, a statement from the US Central Command said: "An initial review of strike data indicates that, at the request of the Iraqi security forces, the coalition struck fighters and equipment, 17 March, in west Mosul at the location corresponding to allegations of civilian casualties."

A coalition investigation into the deadly raid is under way. "We will use the results of those investigations to make sure that our tactics, techniques and procedures take every feasible measure to protect civilians from harm," said Isler.

A military vehicle on the streets of Mosul Khalid al Mousily/Reuters

"The coalition takes every allegation seriously and investigates all credible allegations," he added.

As the Ministry of Defence faced questions over Britain's involvement in the strike, an RAF spokesman said it "continues to provide precision close air support to ground forces engaged in difficult urban combat".

"We have not seen evidence that we have been responsible for civilian casualties so far."