BAGHDAD — US-led airstrikes targeting the Islamic State in Iraq and Syria have probably killed at least 459 civilians over the past year, a report by an independent monitoring group said Monday.
The report by Airwars, a project aimed at tracking the international airstrikes targeting the extremists, said it believed 57 specific strikes killed civilians and caused 48 suspected ‘‘friendly fire’’ deaths. It said the strikes have killed more than 15,000 Islamic State militants.
While Airwars noted the difficulty of verifying information in territory held by the group, which has kidnapped and killed journalists and activists, other groups have reported similar casualties from the US-led airstrikes.
‘‘Almost all claims of noncombatant deaths from alleged coalition strikes emerge within 24 hours — with graphic images of reported victims often widely disseminated,’’ the report said.
‘‘In this context, the present coalition policy of downplaying or denying all claims of noncombatant fatalities makes little sense, and risks handing Islamic State and other forces a powerful propaganda tool.’’
The United States launched airstrikes in Iraq on Aug. 8 and in Syria on Sept. 23 to target the militants. A coalition of countries later joined to help allied ground forces combat the extremists. To date, the coalition has launched more than 5,800 airstrikes in both countries.
The United States has only acknowledged killing two civilians in its strikes: two children who were likely slain during an American airstrike targeting Al Qaeda-linked militants in Syria last year. That same strike also wounded two adults, according to an investigation released in May by the US military.
That strike is the subject of one of at least four ongoing US military investigations into allegations of civilian casualties resulting from the airstrikes. Another inquiry into an airstrike in Syria and two investigations into airstrikes in Iraq are still pending.
Army Colonel Wayne Marotto, a spokesman for the coalition, did not address the report directly, but said ‘‘there is no other military in the world that works as hard as we do to be precise.’’
‘‘When an allegation of civilian casualties caused by Coalition forces is determined to be credible, we investigate it fully and strive to learn from it so as to avoid recurrence,’’ he said in a statement.
Airwars said it identified the 57 strikes through reporting from ‘‘two or more generally credible sources, often with biographical, photographic, or video evidence.’’ The incidents also corresponded to confirmed coalition strikes conducted in the area at that time, it said.
The group is staffed by journalists and describes itself as a ‘‘collaborative, not-for-profit transparency project.”