The UN special representative for Afghanistan has said reports indicate that the civilian death toll from the fighting was "immense", with unverified tolls suggesting more than 100 civilians were killed in the clashes.
Most of the victims were students preparing for university entrance exams in a classroom at the Mawoud Academy in an area of west Kabul where many members of the city's mainly Shi'ite Hazara community live.
Traveling in Bogota on Friday, Defense Secretary Jim Mattis said Western-backed Afghan defenses will not break under the weight of Taliban violence before scheduled parliamentary elections in October.
The spokesman, Najib Danish, says at least 35 people were also wounded in the attack on Wednesday afternoon.
According to the U.S., the Afghan government controls about 56 per cent of the country and the Taliban 11 per cent, while the rest of the territory is under dispute. "In the explosion 37 people were killed, more than 40 injured", he said, adding that the "absolute majority" of them had been students.
No one has so far claimed responsibility for the bombing but officials blame the Islamic State of Iraq and the Levant group, which considers Shiites to be heretics and frequently targets them, attacking their mosques, schools and cultural centers.
ISIL claimed that more than 200 people were killed in Wednesday's attack, which was disavowed by Afghanistan's main insurgent group, the Taliban.
Elsewhere in Afghanistan, four policemen were killed and four were seriously wounded late Wednesday when they tried to defuse a auto bomb they found in southern Kandahar province, according to Zia Durrani, provincial police spokesman.
Azam said that one Army helicopter brought Chinese Camp "three sacks of rice" on August 3, one day after the ISIS captives were taken to Kabul. He blamed insurgents, saying the rockets they fire at Afghan security forces often harm civilians. Dilawar Aymaq, a parliamentarian from Baghlan, confirmed the attack.
Elsewhere in Afghanistan, the Taliban attacked a police checkpoint in the southern Zabul province early Wednesday, killing four policemen, according to the provincial police chief, Mustafa Mayar.
Afghanistan is littered with unexploded ordnance left by decades of war.
Afghan forces appeared to have finally pushed Taliban fighters from the strategic city of Ghazni on Wednesday, as shopkeepers and residents warily returned to the streets after days of intense ground fighting and United States airstrikes.