At least 352 civilians were killed in United States-led strikes against the Islamic State group in Iraq and Syria since the operation began in 2014, the American military establishment said on Sunday, according to Reuters. The military’s tally, however, is far below those of outside groups. Monitoring group Airwars pegged the number of civilian deaths in coalition strikes at more than 3,000, The Guardian reported.

“We regret the unintentional loss of civilian lives...and express our deepest sympathies to the families and others affected by these strikes,” the Pentagon said. “All feasible precautions were taken, but strikes resulted in unintentional loss of civilian life.”

In its monthly assessment of civilian casualties from the US-led coalition’s operations against the extremist group, the Combined Joint Task Force said it was still reviewing 42 reports of civilian deaths. It said 45 civilians had died between November 2016 and March 2017 and 80 from August 2014 to the present that had not previously been announced. The report also mentioned 26 deaths from three separate strikes in March.

Included in Sunday’s tally were 14 civilians killed by a strike in March that had set off a secondary explosion, as well as 10 civilians who died in an offensive against the Islamic State headquarters the same month.