KABUL—A U.S. airstrike in the Afghan city of Kunduz killed at least 19 people at a hospital run by international medical-aid organization Doctors Without Borders early Saturday, prompting condemnation from humanitarian groups and the United Nations.
The organization said 12 Afghan staff members and at least seven patients, among them three children, were killed when its trauma center “was hit several times during a sustained bombing” shortly after 2 a.m. An additional 37 people, including patients and medical staff, were wounded. All international staff members are alive and uninjured, it said.
U.S. Army Col. Brian Tribus, a spokesman for U.S. and coalition forces in Afghanistan, said a U.S. airstrike hit Kunduz city at that hour and “may have resulted in collateral damage to a nearby medical facility.”
The humanitarian group, which is also known as Médecins Sans Frontières, said it had informed all parties involved in the conflict of the precise location of the hospital, most recently on Tuesday. It said the airport was directly hit by a series of bombings at roughly 15 minutes intervals that continued for over an hour even after American and Afghan officials in Kabul and Washington were informed.
“This attack is abhorrent and a grave violation of international humanitarian law,” Meinie Nicolai, the president of MSF, said in a statement. “We demand total transparency from coalition forces. We cannot accept that this horrific loss of life will simply be dismissed as ‘collateral damage.’”
U.S. Army Gen. John Campbell, who commands U.S. and allied troops in Afghanistan, on Saturday called Afghan President Ashraf Ghani to apologize for the incident, according to a statement from Mr. Ghani’s office.
Defense Secretary Ash Carter said that while the U.S. was “still trying to determine exactly what happened,” a full investigation was under way.
Kunduz has been at the center of intense fighting over the past week. The city was stormed by the Taliban on Monday, prompting the U.S. military to carry out at least 12 airstrikes against the militant group to help government forces regain control and to protect U.S. and Afghan troops there.
Kabul said Thursday that it had largely recaptured the city but fighting has continued since, as Afghan forces struggled to dislodge remaining Taliban fighters holed up in buildings across the city.
Saturday’s airstrike, in the heart of the city, indicates that Afghan and Taliban forces are still battling for control of Kunduz.
Around 100 U.S. and coalition special-operations advisers have been deployed in Kunduz to provide tactical guidance to their counterparts.
The U.S. maintains a small military presence in Afghanistan, largely to provide Afghan forces with intelligence and limited antiterrorism operations. This week, its personnel engaged in rare direct ground combat with Taliban fighters in the city.
The Doctors Without Borders hospital, the only advanced trauma center in Kunduz and the surrounding provinces, had been at overcapacity since fighting broke out on Monday, treating around 400 patients.
The airstrike destroyed much of the sprawling compound. The hospital’s main building—where the intensive care unit, emergency rooms and physiotherapy ward were located—was repeatedly hit during each aerial raid, while surrounding buildings were largely unscathed, the organization said. Parts of the hospital were still in flames hours after the attack, as doctors and nurses performed surgery in makeshift facilities.
“The bombs hit and then we heard the plane circle round,” Heman Nagarathnam, an MSF staff member who was at the hospital at the time, said in a statement. “There was a pause and then more bombs hit. This happened again and again.”
The organization treats patients from all backgrounds, including insurgents. However, the Taliban said none of its fighters were in the hospital at the time of the bombing, and condemned the attack.
Afghan security officials said the hospital wasn’t directly hit and that the U.S. airstrike targeted a nearby building where some 60 Taliban and allied Uzbek militants were hiding.
“The airstrike had to be conducted,” one of the officials said. The U.S. military coordinates closely with its Afghan allies on airstrikes, which are usually launched in response to Kabul’s requests.
Nicholas Haysom, who heads the U.N.’s mission in Afghanistan, condemned “in the strongest term the tragic and devastating airstrike.”
The International Committee of the Red Cross and Italian charity Emergency, both of which also operate medical facilities in Afghanistan, also condemned the attack.
“Bombing a hospital where the injured are being treated is an unacceptable act of violence,” Emergency said. Amnesty International called for an independent investigation.
As the Taliban closed in on the city on Monday, Doctors Without Borders said it was assured by both warring parties that the hospital would be protected.
The facility stayed open even as most foreigners, government officials and nongovernmental workers in the city were evacuated, including staff from the U.N., whose offices were subsequently looted by the militants.
The U.S. Embassy in Kabul said Saturday that it remains “deeply concerned about the ongoing violence in Kunduz and the difficult humanitarian situation faced by its residents.”
In the past, U.S. airstrikes that killed civilians strained relations between Washington and Kabul, sparking furious condemnations from former Afghan President Hamid Karzai. Bilateral ties improved under his successor, Mr. Ghani, whose administration embraced tight cooperation with U.S. and allied troops.
Although U.S. airstrikes in Afghanistan have become less frequent as the U.S. military has reduced its presence here, they remain controversial. A U.S. aerial bombing killed 11 Afghan policemen in September in one of the deadliest friendly-fire incidents in the country in recent years. In July, seven Afghan soldiers were killed in a similar incident in the eastern province of Logar.