The United Nations has raised grave concerns about reports of high civilian casualties in the Iraqi city of Mosul.

A senior UN official in Iraq said she was stunned by accounts of “terrible loss of life”, after claims that at least 200 people had been killed in an air strike by the US-led coalition.

US warplanes are supporting the Iraqi army’s mission to retake Mosul from the Islamic State group.

US media reports say an investigation is under way.

It is not known exactly when the deaths are alleged to have happened.

However, reporters in western Mosul’s Jadideh neighborhood said they saw 50 bodies being pulled out of buildings on Friday, after they were razed in air attacks earlier in March.

On the other hand civilians who escaped the besieged Iraqi city said Islamic State gunmen are opening fire on men, women and children as they try to flee Mosul under cover of darkness.

Hungry and exhausted, thousands sloshed through the mud, past wrecked buildings and shattered pavements, to reach an army checkpoint.

Some carried suitcases or bags, others had fled with just the clothes on their backs. They came by foot or piled into carts, and some pushed relatives in wheelchairs