Iraqi authorities have accused Islamic State (IS) militants of using "toxic chemical material" in the battle for Mosul, but they say it has had little effect and that the campaign to liberate Iraq's second-largest city is continuing.

Kurdish militias also take part in operations north and east of the city.

"The bombs used by the Iraqi air force in Mosul are laser-guided and used when we ascertain the nature of the target", Hammah said, Baghdad Post reported.

Officers in Iraq's Federal Police told Reuters that Islamic State shelled government forces with chemical weapons agents in the Urouba and Bab Jadid districts on Saturday.

He added the armed forces get information from the intelligence services.

"We're reaching families who have fled and families who have stayed [but] Mosul has pushed us to our operational limits", said the Humanitarian Coordinator.

The coalition has said it "probably" played a role in civilian casualties in Mosul, while residents have been caught up in fighting between Iraqi forces and IS, and the jihadists are intentionally attacking civilians in the city.

"The battle to recapture the right bank of Mosul is approaches the end, Hammah said, without specifying a date".

It went on to call on the US -led coalition "to give priority to the safety of civilians while carrying out airstrikes against IS".

All five bridges across the Tigris inside Mosul itself have been destroyed in air strikes or by the jihadists.

March 28: The UN says more than 300 civilians have been killed since the start of the west Mosul operation.

The Iraqi Joint Operations Command said Thursday its forces had recaptured 60% of the western flank of Mosul from Islamic State militants. It also said the militants were increasingly using suicide motorbikes attacks.

The Iraqi military said recently that IS has lost more than three-fourths of the territory it seized when it swept across the country in the summer of 2014.