Iraq's military has said that 61 bodies were recovered from a collapsed building that the so-called Islamic State had reportedly booby-trapped in west Mosul.

However, witnesses and local officials said as many as 200 bodies were pulled from the building after a coalition strike last week targeted IS militants and equipment in the Jadida district.

What happened on 17 March remains unclear and details are difficult to confirm as Iraqi forces battle with IS to recapture the densely populated parts of the western half of Mosul, the militant group's last stronghold in Iraq.

Brigadier General Yahya Rasool, the spokesman for the Joint Operations Command, accused IS of gathering civilians together and then blowing up explosives-rigged vehicles nearby to make it look like "Iraqi forces... are targeting innocent civilians".

Eyewitnesses today described horrific scenes from the 17 March blast, with body parts strewn over rubble, residents trying desperately to pull out survivors and other people buried out of reach.

The Iraqi military command said witnesses had told troops that the building was booby-trapped and militants had forced residents inside basements to use them as shields. IS militants had also fired on troops from houses, it said.

"A team of military experts from field commanders checked the building where the media reported that the house was completely destroyed. All walls were booby-trapped and there is no hole that indicates an air strike," it said.

"Sixty-one bodies were evacuated," the statement said.

A coalition air strike had hit the area at the time though there was no sign it struck that building, it said.

As combat continues, the Jadida incident highlights the complexity of the fighting in west Mosul, where militants hide among families, using them as shields and putting at risk as many as half a million people still caught in IS-held areas.

Iraqi forces today hit militant positions with helicopter strikes, and exchanged heavy gunfire and rockets around al Nuri mosque in west Mosul, where the IS declared a caliphate nearly three years ago.

At the north edge of Mosul, Iraqi army divisions raided and entered the Badush cement factory, to where militants had retreated, Lt. Col. Ali Jassem of the 9th armoured division said. Army units are clearing villages to the north.

Thousands of people have already fled Mosul and coalition officials and Iraq's Shi'ite-led government are wary of incidents that could alienate residents of the mainly Sunni city and fuel the kind of sectarian tensions that helped IS to rise.

The US-led coalition backing Iraqi forces said yesterday that it carried out a strike on IS militants and equipment in the area of the reported deaths, and was investigating. It did not give figures for any casualties or details of targets.