JALALABAD, Afghanistan — A nearly seven-hour assault by extremists on a school for midwives in eastern Afghanistan killed three people and wounded 10 others, but authorities managed to avert a far greater catastrophe.

Most of the 67 young female students were removed from the building quickly or fled to a fortified safe room on the grounds of the school in Jalalabad, the capital of the eastern Nangarhar province. Three of the young women were wounded, according to a police official.

Twelve children in a day care center for the school’s staff escaped harm, authorities said.

Attahullah Khogyani, spokesman for the provincial governor, said two security guards and a male driver were killed when the attack began near the school’s gate, the Associated Press reported.

In addition to the three injured women, the wounded included three security officers, two civilians, and two government employees, Khogyani said.

Gholam Sanayi Stanikzai, police chief for Nangarhar province, said the attack ended after two suicide attackers, who had been fighting with automatic weapons and grenades, detonated their explosive vests as the police closed in.

“The reason that it took such a long time to subdue the attack was the presence of women and children inside the center, who were badly scared,’’ Stanikzai said. “Security forces proceeded very carefully.’’

According to witnesses, a large group of the midwifery students barricaded themselves in a safe room. The fate of the children in the day care was unclear for several hours.

The attack began about 11 a.m. at the Midwifery Training Center in Jalalabad, as the assailants laid siege to the school. Five explosions were heard at the site. Heavy gunfire could be heard after the initial attack, and police special forces units arrived on the scene.

The school’s students, most of them 18 to 19, were enrolled in a two-year midwifery program and lived in a dormitory in the center’s compound.

Although there was no immediate claim of responsibility, the attack bore the hallmarks of the Islamic State, whose local affiliate is especially active in Nangarhar and responsible for many suicide attacks there.

The Taliban have recently disavowed attacks on civilian targets and have long refrained from targeting medical facilities or women’s institutions. The Taliban spokesman, Zabihullah Mujahid, denied the group was behind the attack in a WhatsApp message.

The midwife center is run by the Afghan Ministry of Public Health, and it trains midwives for remote districts, where doctors are rare and most women will not go to male doctors.

It’s close to another midwifery school in Jalalabad that is run by the Norwegian Afghanistan Committee. That organization’s country director, Terje M. Watterdal, said the young women there were all safe but spent the hours of the attack in a safe room as well.

Nangarhar province, in eastern Afghanistan, has been the site of previous attacks on civilians.

On July 22, gunmen opened fire on worshipers in a mosque in Nangarhar, killing four people, according to a provincial official. Three other people, including the mosque’s religious leader, were wounded in the attack.

On the same day, an Islamic State suicide bomber struck near Kabul’s airport, killing 20 people and narrowly missing Afghanistan’s vice president, who was returning home after living in Turkey for more than a year.