KABUL — U.S. airstrikes in May on suspected Taliban drug facilities killed 30 civilians, the United Nations said Wednesday in a detailed report on the incident. The U.S. military disputed the claims, arguing that all those killed in the strikes were combatants.

The strikes targeted drug labs run by the Taliban that produce methamphetamine.

The U.S. military said the workers in those labs are legitimate targets because the “personnel in the labs were members of the Taliban,” according to a statement released by the media office of U.S. forces in Afghanistan on Wednesday. 

The U.S.-led mission in Afghanistan “disputes the findings, legal analysis, and methodology” of the U.N. report, according to the statement, and questions “their reliance on sources with conflicted motives or limited knowledge . . . and their narrow definition of legally targetable combatants.”

The United Nations said under international law “facilities that contribute economically or financially to the war effort . . . are considered civilian objectives.” The U.N. report determined strikes on more than 60 sites killed 30 civilians and wounded five. The strikes were carried out in Afghanistan’s western Farah and Nimruz provinces.

The dispute surrounding the drug lab strikes reflects the difficulty of separating civilians from combatants as Afghan government troops battle an insurgency with support from U.S. forces.

The United States “is fighting in a complex environment against those who intentionally kill and hide behind civilians, as well as use dishonest claims of noncombatant casualties as propaganda weapons,” read the statement from U.S. forces in Afghanistan.

The Taliban said the U.N. report “proved that Americans are engaged in heavy war crimes,” according to a statement released to the media Wednesday. 

The large number of civilians killed during operations against militants has stoked anger across Afghanistan.

In April, the United Nations found that during the first quarter of 2019, forces allied with the Afghan government were responsible for more civilian deaths than the Taliban and other insurgents

That shift comes as U.S. and Afghan government forces have stepped up ground and air offensives targeting the Taliban and sources of the group's income. The increased pressure came as both the United States and the Taliban attempted to pressure the other into a peace deal

The U.N. report on the drug lab strikes said the casualty numbers should be taken as a minimum because the organization investigated allegations of more than 100 civilian casualties.

Those determined killed and wounded in the report were subjected to multiple verification methods. U.N. investigators conducted site visits as part of the investigation. 

The U.S. military said that before the strikes were carried out, U.S. forces observed the sites for “scores of hours,” providing “the degrees of certainty required at the time of the precision strikes to assess forces were only striking legal targets and avoiding noncombatant casualties and collateral damage.”

The United States has tried for years to curb the Taliban’s multimillion-dollar drug trade.

U.S.-funded efforts to combat narcotics in Afghanistan came under severe criticism from a U.S. government watchdog in a report last year that said opium production and drug addiction is rapidly escalating despite efforts costing more than $8 billion since 2002.

Correction: An earlier version of this story inaccurately described the number of civilians the United Nations claimed in a report were killed by U.S. airstrikes. The report lists 30 civilian deaths, not 40.