The operation to retake Mosul from IS started last October.
In the Old City, more than 40 civilians were killed when ISIL caught them trying to escape, said a resident of the Farouq district where the symbolic Nuri mosque is located.
Al-Nujaba is one of the groups accused by human rights organisations of killing scores of fleeing civilians in the Syrian city of Aleppo past year.
Lt. Gen. Stephen Townsend, the top USA general commanding the fight against Islamic State in Iraq and Syria, has said there was "at least a fair chance" that the USA -led coalition was responsible for the strike, but if so, it was "an unintentional accident of war, and we will transparently report it to you".
The militants are dug in surrounded by civilians, effectively using them as human shields and taking advantage of the narrow streets of the Old City that restrict the movements of the Iraqi forces and limit the use of artillery and air power. "I have no news", he said.
A USA -led coalition has been providing air and ground support to Iraqi forces battling the militants, allowing them to recapture most cities they had overran in 2014 in Sunni areas of northern and western Iraq.
US-led coalition air strikes killed up to 200 civilians in Mosul last month after militants reportedly forced them inside a cluster of buildings, then stationed its snipers on top. For now, the 43-year-old is treating a man in his forties with facial injuries.
These doctors used to work in Mosul but fled the tyrannical rule of the jihadists.
Many Iraqis have been trying to flee to areas held by Iraqi forces as the battle between US-backed troops and the extremist militia continues in Iraq's second-largest city. The Athbah field hospital opened on March 24 with support from the World Health Organization and the Iraqi health authorities.
Basic goods have been unavailable for months and the little food that is left is either too expensive or hoarded by the jihadists.
The Mosul battle has lasted almost six months and supplies have dwindled sharply as Iraqi forces secured the city's east bank and sealed their siege on the jihadists' last redoubts on the west side.
"Nearly all our patients suffer from malnutrition", says Taryn Anderson, head nurse at the Athbah clinic.
An estimated 334,000 people are now displaced in total as a result of fighting in both east and west Mosul, according to the Iraqi authorities. "They are our neighbors, our families".