The United Nations mission in Afghanistan announced Monday that the death toll from a suicide bombing that occurred at an education center in the Afghan capital last week had increased to at least 43.

Reports revealed that a suicide bomber blew himself up next to a women at a gender-segregated study hall in a Kabul neighborhood Friday.

"Forty three killed. 83 wounded. Girls & young women were the main victims," the UN mission said in a tweet, adding that casualties were expected to rise further.

The bomber detonated as hundreds of students were gathered ahead of an entrance exam for university admissions.

The Taliban authorities have so far said 25 people were killed and 33 others were wounded in the attack.

Following the Taliban's return to power in Afghanistan last year, a two-decade war against the Western-backed government came to an end, and there was a dramatic drop in bloodshed. However, security has started to deteriorate recently.

Earlier this week, Kabul's Kaaj educational center was the location of a suicide bombing on September 29 that left 19 killed and more than 20 injured. The official death toll is likely to rise, according to eyewitnesses.

The area in which the attack occurred has a majority population of Hazara, the ethnic minority group often targeted by the Islamic State. 

Kabul police spokesperson Khalid Zadran confirmed the number of injuries amounting to 27 people, down after a revision of the 29 announced initially, adding that the blast occurred during the time when an entrance exam was being taken.

Schools and educational institutions are usually closed on Fridays, the day of the bombing, in Afghanistan.