KABUL, Afghanistan — A suicide bomber struck a private education center in a Shiite neighborhood of Kabul on Wednesday where high school graduates were preparing for university entrance exams, killing 48 young men and women and leaving behind a scene of devastation.

The bombing, blamed on the Islamic State, was the latest assault on Afghanistan’s Shiite community, increasingly targeted by Sunni extremists who consider Shiites heretics.

It's unclear how the bomber snuck into the center for college-bound youths in the Dasht-i Barcha area of Kabul, Afghanistan. A city official blamed the Islamic State for the bloodshed. Associated Press/Rahmat Gul

It also showed how militants are still able to stage large-scale attacks, even in the heart of Kabul, and underscored the struggles of Afghan forces to provide security on their own.

The attack comes amid a particularly bloody week in Afghanistan that has seen Taliban attacks kill scores of Afghan troops and civilians.

It was not immediately clear how the bomber snuck into the education center in the Dasht-i Barcha area of Kabul.

The spokesman for the public health ministry, Wahid Majroh, said 67 people were also wounded in the bombing and that the death toll – which steadily rose in the immediate aftermath of the bombing – could rise further. He did not say whether all the victims were students and whether any of their teachers were also among the casualties.

Dawlat Hossain, father of 18-year-old student Fareba, who had left her class just a few minutes before the bombing but was still inside the compound, was on his way to meet his daughter and started running when he heard the explosion.

Hossain recounted how when he entered Fareba’s classroom, he saw parts of human bodies all over student desks and benches.

“There was blood everywhere, all over the room, so scary and horrible,” he said. After finding out that his daughter was safe, he helped move the wounded to hospitals.

Fareba was traumatized that so many of her friends were killed, but Hossain said she was lucky to be alive.

The explosion initially set off gunfire from Afghan guards in the area, leading to assumptions that there were more attackers involved, but officials later said all indications were that there was only one bomber.

No group immediately claimed responsibility for the attack but Jawad Ghawari, a member of the city’s Shiite clerical council, blamed the Islamic State, which has carried out similar attacks on Shiites in the past, hitting mosques, schools and cultural centers. In the past two years, there were at least 13 attacks on Shiites in Kabul alone, he said.

Afghan President Ashraf Ghani condemned the “terrorist” attack that “martyred and wounded the innocent” and ordered an investigation.

“By targeting educational and cultural centers, terrorists have clearly shown they are against all those Islamic principles (that strive) for both men and women to learn and study,” Ghani said in a statement.

The head of the U.N. children’s agency denounced the attack, saying it’s “deplorable” that children continue to be hardest-hit in the growing violence across Afghanistan.

Meanwhile, a Taliban assault on two adjacent checkpoints in northern Afghanistan late Tuesday night killed at least 30 soldiers and police officers.

The attack took place in Baghlan province’s Baghlan-I Markazi district, said Mohammad Safdar Mohseni, the head of the provincial council. Dilawar Aymaq, a parliamentarian from Baghlan, said the attack targeted a military checkpoint.

At least nine security forces were still missing and four others were wounded in the attack, said Abdul Hai Nemati, the governor of Baghlan.

Taliban spokesman Zabihullah Mujahid claimed responsibility for the assault.