WASHINGTON — New data show air and ground strikes near the Iraqi city of Mosul have resulted in nine civilian deaths and injuries to three others in the ongoing battle against the Islamic State, the U.S.-led military coalition announced Saturday.

The casualties are the latest sign of the challenges facing the Pentagon as it launches daily bombing raids against Sunni extremist fighters who often mix among civilians in densely populated cities.

The figures, released in a monthly report compiled by the U.S. military, bring the Pentagon’s total official civilian death toll to 229 since the air war against the Islamic State group began nearly three years ago.

Independent monitors say far more people have died as a result of the airstrikes.

The issue of civilian deaths has attracted new international attention since the release of vivid images of a March 17 airstrike in the Jadidah neighborhood in western Mosul that allegedly killed 200 or more Iraqi citizens. That airstrike is currently under investigation.

The U.S.-led military coalition launches airstrikes and ground-based artillery attacks each day in support of Iraqi and Syrian forces.

The military said Saturday that it had received 41 new reports of possible civilian casualties from recent months. It has examined 17 claims; 12 were dismissed as “non-credible,” while five were deemed valid. Military officials are still reviewing the remaining allegations.

Humanitarian groups estimate that hundreds of civilians have been killed or wounded in the more than 19,300 airstrikes and ground artillery attacks launched by the U.S. and its allies since August 2014.

Airwars.org, a nonprofit group that uses social media and witness accounts to track casualties, estimates that coalition airstrikes have killed 2,831 civilians.

“We’re certainly glad that the coalition is taking civilian casualties and their reduction seriously,” said Chris Woods, director of Airwars. “Our concern here is that even with the coalition looking at many more cases than they did a while back, they still can’t keep up with all the allegation.”

The military summarized the findings of its investigations in a six-page news release that did not identify any of the victims. All of the incidents were reported to have occurred “near Mosul.”

According to the release, four civilians were unintentionally killed and two injured on Sept. 20, 2015, when an airstrike hit “what was evaluated at the time to be an ISIS headquarters building.” ISIS is an acronym for the Islamic State.

Another civilian was unintentionally killed in a Jan. 30, 2017, strike against an Islamic State weapons manufacturing facility.

During a Feb. 6 strike, the military assessed that three civilians were “unintentionally injured when they entered the target area.”

Two more civilians were “unintentionally killed when they entered the target area” on Feb. 12, and a similar incident occurred four days later, the report said, on a bomb-making facility where two civilians were killed.

The military said all strikes complied with laws on armed conflict and “all feasible precautions” were taken.

Los Angeles Times staff writer Molly Hennessy-Fiske in Irbil, Iraq, contributed to this report.

William.hennigan@latimes.com