An air strike targeting Islamic State militants that killed at least 100 people was launched by the US military, American officials say.
In the days following the March 17 air strike, US officials had said they were unsure whether American forces were behind the attack.
The statement issued on Saturday by the US-led coalition said the air strike had been requested by Iraqi security forces to target IS fighters and equipment "at the location corresponding to allegations of civilian casualties".
US-backed government troops were fighting IS forces in that area of western Mosul, the statement said.
The coalition said it takes all allegations of civilian casualties seriously and a formal Civilian Casualty Credibility Assessment has been opened to determine the facts surrounding this strike and the validity of the allegation of civilian casualties.
"Our goal has always been for zero civilian casualties, but the coalition will not abandon our commitment to our Iraqi partners because of ISIS's inhuman tactics terrorising civilians, using human shields, and fighting from protected sites such as schools, hospitals, religious sites and civilian neighbourhoods," the coalition said.
Altaf Musani, representative of the World Health Organisation in Iraq, told The Associated Press in the Jordanian capital of Amman that the organisation's priority was quick treatment for those wounded.
"It is our understanding that there was an incident and we have worked with the local health actors and they have confirmed more than 100 are dead," Musani said.
Musani said that since the operations in Mosul began in October, there have been at least 5300 people referred to hospitals in and around the city. He added that since the attack on western Mosul began last month, "we have managed to capture more than 1300" cases.
"When you take a better look at what those numbers mean, what is worrying for the WHO and aid actors is that roughly 30 per cent of the total numbers are women," he said.
"Roughly 30 per cent of that large number are children under 15, and that is deeply concerning because of the capacities needed to treat those wounded coming out of the front lines."
US President Donald Trump campaigned on a promise to dramatically ramp up the assault on Islamic State militants and has vowed to eradicate it.
