Tens of other people were wounded, according to public health officials.
ADVERTISEMENTA suicide bomber struck a voter registration center in the Afghan capital on Sunday, killing at least 57 people.
Public Health Ministry spokesman Wahid Majro said tens of others were wounded in Sunday's attack, updating an earlier toll. Gen. Daud Amin, the Kabul police chief, said the suicide bomber targeted civilians who had gathered to receive national identification cards.
The large explosion echoed across the city, shattering windows miles away from the attack site and damaging several nearby vehicles. Police blocked all roads to the blast site, with only ambulances allowed in. Local TV stations broadcast live footage of hundreds of distraught people gathered at nearby hospitals seeking word about loved ones.
The Islamic State group claimed responsibility for the attack in a statement carried by its Aamaq news agency, saying it had targeted Shiite "apostates." NBC News has not verified the claim.
Afghanistan will hold parliamentary elections in October.
Last week, three police officers responsible for guarding voter registration centers in two Afghan provinces were killed by militants, according to authorities.
Afghan security forces have struggled to prevent attacks by the Islamic State affiliate as well as the more firmly established Taliban since the U.S. and NATO concluded their combat mission at the end of 2014. Both groups regularly launch attacks, with the Taliban usually targeting the government and security forces, and Islamic State targeting the country's Shiite minority.
Both groups want to establish a harsh form of Islamic rule in Afghanistan, and are opposed to democratic elections.
The Taliban routinely target security forces and government officials with roadside bombs, which often end up killing civilians.