The Pentagon on Friday acknowledged that the U.S.-led coalition fighting the Islamic State in Iraq and Syria carried out an airstrike in a western Mosul neighborhood and that it is “looking into” reports that the bombing left more than 100 civilians dead.

“We are aware of reports on airstrikes in Mosul resulting in civilian casualties,” Eric Pahon, a Pentagon spokesman, said in a statement to Fox News. “The Coalition conducted several strikes near Mosul and [coalition forces are] looking in to these reports. The Department of Defense takes all reports of civilian casualties very seriously and assesses all incidents as thoroughly as possible.”

The suspected civilian body count underscores the problems that Iraqi troops face in their weeks-long campaign to drive out the Sunni militant group from the densely urban part of Iraq's second-largest city.

Residents of the neighborhood where the airstrike occurred, known as Mosul Jidideh, told a team of Associated Press reporters at the scene that scores of residents are believed to have been killed by a pair of airstrikes that hit a cluster of homes in the area earlier this month.

"Over 137 people were inside. The entire neighborhood was fleeing because of missiles that hit, so people were taking refuge here," said Ahmed Ahmed, one of the residents of the neighborhood.

One airstrike hit the residential area on March 13, followed by a second strike four days later, the residents said.

The Department of Defense takes all reports of civilian casualties very seriously and assesses all incidents as thoroughly as possible. — Eric Pahon, a Pentagon spokesman

Faced with their most difficult fight yet against ISIS, Iraqi and the U.S.-led coalition forces have increasingly turned to airstrikes and artillery to clear and hold territory in Iraq.

As of March 14 of this year, the U.S. alone has carried out over 7,700 airstrikes in Iraq -- many centered around the ISIS stronghold in Mosul – while coalition forces have conducted an additional 3,634 airstrikes in the war-plagued Middle Eastern nation. The military intervention against ISIS – dubbed Operation Inherent Resolve – has involved almost 19,000 airstrikes in Syria and Iraq since 2014.

The Pentagon’s announcement on Friday comes two days after it reported it was investigating claims that a U.S. military airstrike recently hit a school in northern Syria and allegedly killed dozens of civilians. The Syrian Observatory for Human Rights, a Britain-based monitoring group, said that at least 33 bodies were pulled from the rubble at the school, which had housed at least 50 families fleeing violence elsewhere in the war-torn nation.

Dozens of civilians were also purportedly killed last week when a strike on an al-Qaida target blasted a prayer hall in the town of Jinah, in Syria’s Aleppo province. While the Pentagon, which opened an investigation into the bombing, said that numerous al-Qaida fighters were killed in the strike, local residents claim the dead were civilians who had gathered for a religious class.

The Pentagon, which has yet to release casualty figures from last month's fighting, has acknowledged 220 civilian deaths from coalition airstrikes in Iraq and Syria since its campaign against ISIS began in 2014. Independent monitoring groups, such as the London-based Airwars, put the casualty figures much higher, at just over 2,700 killed by coalition strikes since 2014.

The U.S. is conducting strikes on IS daily from bases in Jordan, Turkey and elsewhere in the region. U.S. military commanders have also raised the prospect of sending additional forces into the region to be ready to assist in accelerating the fight in either Syria or Iraq.

Fox News' Lucas Tomlinson and The Associated Press contributed to this report.