Air strikes have killed dozens of civilians in west Mosul in recent days, officials said Saturday, as the number of people fleeing fighting against jihadists in the area topped 200,000.
Hundreds of thousands more are still in danger inside the city, where Iraqi forces have recaptured a series of neighbourhoods since the operation to retake west Mosul from the Islamic State group began last month.
Both Iraqi aircraft and those from an international US-led coalition are carrying out strikes against IS in the Mosul area.
The coalition said it struck an area in west Mosul on March 17 in which civilian casualties were reported, and that it was investigating "to determine the facts surrounding this strike and the validity of the allegation of civilian casualties".
But some Iraqi officials referred to more than one day of strikes.
"There are dozens of bodies still under the rubble," Bashar al-Kiki, the head of the Nineveh provincial council, told AFP.
"Efforts to remove the bodies... are ongoing."
Nawfal Hammadi, the governor of Nineveh province of which Mosul is the capital, said the coalition was responsible for the strikes in the city's Mosul al-Jadida area.
Hammadi had put the toll at "more than 130 civilians" killed, but later referred to "the burial of hundreds of martyrs under the rubble of the houses in the Mosul al-Jadida area".
"The Daesh terrorist organisation is seeking to stop the advance of the Iraqi forces in Mosul at any cost, and it is gathering civilians... and using them as human shields," he said, using an Arabic acronym for IS.
- Residential buildings hit -
Other officials also said that hundreds of people had been killed. It was not possible to confirm the tolls independently.
Omar Mohanned Sumayr and his uncle Manhal, both of whom have now fled Mosul, said that a building with 170 people inside next to their own house had been destroyed when IS forces in the area were targeted from the air.
"The house fell on the heads of the families," Sumayr said, adding that all 170 people inside were killed.
He said IS fighters and an explosives-rigged vehicle were targeted, while Manhal said IS sniping had prompted the strike.
"Daesh snipers went up on the houses and opened fire on the Iraqi forces," after which a plane targeted them with a missile, Manhal said.
An Iraqi brigadier general said that bombing had damaged more than 27 residential buildings and that three were completely destroyed.
The officer, who spoke on condition of anonymity, said the strikes came after IS targeted military aircraft and attacked Iraqi forces with sniper fire.
The US-led coalition against IS, which has been bombing the jihadists for more than two and a half years, said Saturday it had struck a location in west Mosul where civilians were reportedly killed.
- 'Terrible loss of life' -
"An initial review of strike data... indicates that, at the request of the Iraqi security forces, the coalition struck (IS) fighters and equipment, March 17, in west Mosul at the location corresponding to allegations of civilian casualties," it said in a statement.
At the beginning of this month it had said that "it is more likely than not, at least 220 civilians have been unintentionally killed by coalition strikes", while other incidents were still under investigation.
The United Nations said it was "profoundly concerned" by the reported deaths from the Mosul air raids, and called for all parties to protect civilians during the battle.
"We are stunned by this terrible loss of life and wish to express our deepest condolences to the many families who have reportedly been impacted by this tragedy," Lise Grande, the UN's humanitarian coordinator for Iraq, said in a statement.
"Nothing in this conflict is more important than protecting civilians.
"International humanitarian law is clear. Parties to the conflict -- all parties -- are obliged to do everything possible to protect civilians. This means that combatants cannot use people as human shields and cannot imperil lives through indiscriminate use of fire-power," she said.
More than 200,000 people have fled west Mosul since Iraqi forces launched the operation to retake it on February 19, an Iraqi ministry said Saturday.
"The number of displaced from the areas of the right bank (west side) of the city of Mosul has risen to 201,275 people," the ministry of migration and displaced said in a statement.
The UN said Thursday that around 600,000 people were left in west Mosul, 400,000 of them "trapped" in the Old City area under siege-like conditions.