UN 'deeply disturbed' over Mosul civilian deaths

The outcry comes after 18 people who were fleeing the fighting in the town of Hawijah died when roadside bombs destroyed the truck they were being transported in by Iraqi security forces on Friday.

"We are deeply disturbed by reports of civilian deaths and injuries from crossfire and improvised mines, forced recruitment of children and the use of families as human shields in areas under control of IS," said Lise Grande, the Humanitarian Coordinator for Iraq.

"Major efforts are being made by the Iraqi security forces to protect civilians. All the parties to the conflict - all of them - are obliged under international humanitarian law to do everything possible to protect civilians and ensure they have access to the assistance they deserve and need," she added.

The major military campaign to oust IS from Iraq's second city got underway three weeks ago and has so far seen 30,000 civilians displaced.

As Iraqi forces breach the city walls, aid agencies expect a mass exodus of one million residents.

The UN's refugee agency UNHCR is providing 11 camps in northern Iraq to receive thousands of displaced people.

The latest refuge opened on Friday following the largest displacement - some 8,000 people - since operations began.

Those fleeing the fighting risk being exposed to bombs planted by IS, as well as the extreme danger of being caught in the crossfire between security forces and the militants, including being used as human shields by IS fighters.

Fires set to oil wells have also worsened the humanitarian crisis, with reports of residents struggling to breathe under a toxic cloud of smoke.