Forty-six girls and young women were among those killed in a suicide bombing on an Afghan education centre last week, the UN said Monday as it announced the total death toll had risen to 53.

A suicide bomber blew himself up on Friday next to women at a gender-segregated study hall packed with hundreds of students sitting a practice test for university admissions.

The attack happened in a Kabul neighbourhood home to the historically oppressed Shiite Muslim Hazara community, which has been subjected to some of the worst violence in the country's recent history.

"Our human rights team continues documenting the crime: verifying facts & establishing reliable data to counter denial & revisionism," the United Nations assistance mission in Afghanistan (UNAMA) tweeted.

It raised the death toll from 43 to 53, adding that a further 110 had been wounded.

Afghanistan's Taliban authorities, which have often tried to play down attacks challenging their regime, have said 25 people were killed and 33 others wounded.

No group has so far claimed responsibility, but the jihadist Islamic State group (IS), which considers Shiites as heretics, has carried out several deadly attacks in the same area targeting girls, schools and mosques.

Education is a flashpoint issue in Afghanistan, with the Taliban blocking many girls from returning to secondary education, while IS also stands against the education of women and girls.

The Taliban's return to power in Afghanistan last year brought an end to a two-decade war against a Western-backed government, leading to a significant reduction in violence, but security has begun to deteriorate in recent months.

Friday's attack has triggered sporadic women-led protests in Kabul and some other cities.

Around 50 women chanted, "Stop Hazara genocide, it's not a crime to be a Shiite", as they marched on Saturday in the Dasht-e-Barchi neighbourhood where the attack happened.

The rallies have been dispersed by Taliban forces often firing shots into the air and beating protesters.

Afghanistan's Hazaras have regularly faced attacks in the majority Sunni Muslim country.

They have been persecuted for decades, targeted by the Taliban during their insurgency against the former US-backed government as well as by IS.

In May last year, before the Taliban's return to power, at least 85 people -- mainly girls -- were killed and about 300 were wounded when three bombs exploded near their school in Dasht-e-Barchi.

Again, no group claimed responsibility, but a year earlier IS claimed a suicide attack on an educational centre in the same area that killed 24.