US coalition strikes against ISIS killed at least 352 civilians since 2014, Pentagon says Pentagon says at least 352 civilians have died in ISIS fight since August 2014.

 -- A new Pentagon report finds at least 352 civilians have been unintentionally killed by artillery and airstrikes in the U.S. coalition fighting ISIS in Iraq and Syria since the operation began in August 2014, according to the Pentagon.

The U.S. military's Combined Joint Task Force for the operation targeting ISIS said in the statement that the total includes 45 civilian deaths for which investigations were completed in March.

"Although the coalition takes extraordinary efforts to strike military targets in a manner that minimizes the risk of civilian casualties, in some incidents casualties are unavoidable," the task force said in its report.

Among the recent incidents listed, 14 civilians were killed March 1 when a strike on an ISIS factory producing explosive devices set off a secondary blast near a house down the street near Mosul, Iraq.

Two days later, on March 3, ten civilians were unintentionally killed during a strike against an ISIS headquarters near Mosul.

Some watchdog groups tabulate reports of civilian deaths and report numbers higher than those from the U.S. military.

The Pentagon statement Sunday said the military is "unable to investigate all reports of possible civilian casualties using traditional investigative methods, such as interviewing witnesses and examining the site."

To help determine civilian deaths, the coalition "interviews pilots and other personnel involved" in targeting strikes, reviews any strike or surveillance video available, and "analyzes information provided by government agencies, nongovernmental organizations, partner forces and traditional and social media," the statement said.

The report also indicated that the Pentagon is still assessing reports that a coalition airstrike on March 17 played a role in the deaths of as many as 200 civilians in western Mosul.

The top U.S. commander in Iraq, Lt. Gen. Stephen Townsend, said in late March that there is "a fair chance" that the airstrike played a part in the deaths of the civilians inside three leveled buildings.

Townsend told reporters at the time that the U.S. was reviewing the incident and may find that the civilian deaths were due to a combination of the airstrike and the ISIS tactic of using human shields inside the buildings.

ABC News' Lucien Bruggeman and Luis Martinez contributed to this report.