KABUL, Afghanistan — Sayed Ul-Shuhada school in Kabul was once a place of tentative hope. Impoverished Afghan children studied there: girls and boys who worked as carpet weavers to pay for their books. An Afghan aid group donated a library and teachers helped students paint colorful murals.On Saturday, it became the site of one of Afghanistan's worst attacks in at least a year, when a series of blasts appeared to deliberately target its female students.A car bomb and at least two other blasts detonated near the school gates just as the girls and young women were streaming out, says Sharifa Danishjo, an 11th grader wounded in the blast."I heard the sound of the blast, then everyone started running, screaming," said Danishjo. "I ran back [toward the school] because my sister was still in class, but then another blast happened. I saw a friend who was with me — but half her body was not there, from her waist down."Danishjo says she then fainted.More than 50 people were killed, most of them girls and young women, according to Tariq Arian, a spokesman for the Afghan interior ministry. The death toll may in fact beover 80.As American and foreign forces withdraw, some see the school attack as a portent, as Afghan security forces grapple with multiple, simultaneous threats without U.S. support for airstrikes and local training.The school — in Kabul's Dasht-e-Barchi neighborhood, which has been repeatedly targeted in attacks— runs several shifts, including one for high school girls in the afternoons. Saturday's attack was timed to target that specific shift.Walking out of the gate as the car exploded was Ruqia Bakhahishi, a 14-year-old seventh grader. From her hospital room, she learned that shrapnel tore through her body and passersby took her to one hospital, but it was already full with other wounded girls. Then they rushed her to the Mohammad Ali Jinnah hospital, where she underwent three surgeries on her legs and stomach.That hospital is also where Muhammad Hassan eventually found his 17-year-old daughter Tahira, after he searched through debris, notebooks and shoes left behind after the attack."She's in shock," he says. "She laughs, and then she cries for an hour. She hits herself. She says the attack keeps coming back to her."When the Taliban ruled Afghanistan, they banned girls from attending school. In the two decades since they were toppled, activists, officials and international aid donors have built schools and tried to make them safe for girls. The results have been mixed — but there's also been progress. About a third of all students in Afghan schools are girls, with more than 3.5 million enrolled, according to the U.S. Agency for International Development.So this attack was particularly devastating."It felt like my heart fell down off my chest — like it actually fell down to pieces," says Freshta Karim, the founder of Charmaghz, an education charity that runs five mobile libraries across Kabul. "Also, right now, I have a moral dilemma. Should we ask children to go to school when the schools are not safe for them? Can we do that?"Many Afghan parents may keep their girls home after this, warns Heather Barr, the interim co-director of the women's rights division of Human Rights Watch. Barr previously was an Afghanistan researcher for the group, and spent days at the Sayed Ul-Shuhada school while she worked on a report about education."Of course, you want your kid to get an education, but you're also terrified of her going to school and not coming home," Barr says. "So I think this attack is going to push thousands of girls out of school. On that level, it doesn't matter who did it. It doesn't matter if there's going to be more or not. It's done, and it's going to cause the harm it's going to cause."No group claimed responsibility, but ISIS militants have launched similar attacks in the same area of Kabul, which is overwhelmingly Hazara — an ethnic minority that is overwhelmingly Shiite, also a minority in a country that is predominantly Sunni.The Taliban denied involvement in the attack. After it occurred, they announced a three-day ceasefire for the Eid holiday marking the end of the holy month of Ramadan later this week. The ceasefire is meant to begin Wednesday or Thursday, depending on the sighting of the moon.American and other international forces are expected to leave by Sept. 11, winding up two decades of involvement in Afghanistan."The Afghan war is entering into a new phase, and it is going to be bloody [and] multilayered," says Tamim Asey, the executive chairman of the Institute of War and Peace Studies, a Kabul-based think tank. This new phase "will have elements of proxy war, civil war."Foreign forces are leaving no matter what, says Michael Kugelman, the South Asia senior associate at the Wilson Center."President Biden was quite clear that the main reason why he's decided to pull troops is that he feels that the the terrorist threat directed at U.S. interests ... emanating from Afghanistan is not sufficiently strong to warrant U.S. forces staying," he says. "As horrific as this attack was, this is not the type of thing that would that would cause the U.S. to to change course, because these are attacks that target Afghans."From their hospital, some of the girls who survived the attack are defiant.As her father fusses over her, Tahira, the wounded 17-year-old, says she's got a message for other Afghan girls: "Don't bow down to this oppression. Continue school."She's going back too, she insists — as soon as she can.Ghani reported from Kabul. Hadid reported from Sydney, Australia. Copyright 2021 NPR. To see more, visit https://www.npr.org.