But a Kunduz police spokesman, Sayed Sarwar Hussaini, said Taliban fighters had entered the hospital and were using it as a firing position. The hospital treated the wounded from all sides of the conflict, a policy that has long irked Afghan security forces. In a Twitter post, Arjan Hehenkamp, director of Doctors Without Borders in the Netherlands, denied that Taliban fighters had been in the hospital, saying that only staff, patients and caretakers had been inside.

Video of the hospital grounds posted Saturday showed fires still burning, blackened walls and, in one building, a collapsed ceiling. One side of one building appeared to be pockmarked by bullets or possibly shrapnel, suggesting that there could have been fighting there. But it was impossible to tell whether the marks were new.

The organization described the facility as “very badly damaged.”

The United States Embassy in Kabul said it “mourns for the individuals and families affected by the tragic incident at the Doctors Without Borders hospital, and for all those suffering from the violence in Kunduz.” A hospital nurse, who asked not to be identified because he had instructions not to speak to reporters, said that two nurses had been killed, as well as at least three doctors, a pharmacist and two guards. “Most of my colleagues died in the fire after the bombing,” he said.

“When the bombing occurred we were treating patients, then we lost our way. Everyone stumbled and fumbled to escape,” the nurse said. “I don’t even remember how I got out.”

Another nurse described treating himself because there was no one to help him.

Doctors Without Borders said 105 patients and caretakers had been at the hospital, along with 80 staff members. The hospital was “partially destroyed” in the bombing, the group said, adding that it had been “hit several times.”

When the military describes a single airstrike, it can mean that more than one bomb was dropped on a single target. Similarly, if an attack is carried out by helicopters or drones, there may be more than one missile or rocket fired, but if there is a single target, it is often described as just one airstrike, according to the military.