Most of the victims were young men and women, high school graduates preparing for university entrance exams in the Shiite area's educational center when the bomber walked into the building and blew himself up.
"We received around a hundred dead bodies - most of which were security forces and police but also there were some civilians among them", said Abdul Basir Ramaki, the head of Ghazni provincial hospital.
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.
It said 57 people were wounded in the bombing, part of spate of attacks against a branch of Islam that ISIL considers heretical. The remaining victims will be taken to their villages to be buried there, said Gulam Hassan, the cousin of one of the victims. He had been nearby when he heard the blast, and ran to the center, he told AFP.
The brief respite sparked hopes the truce could clear the way for talks to end the almost 17-year-old conflict. "Now... I am not sure he will survive".More news: Chelsea boss Maurizio Sarri not anxious about Alvaro Morata’s dip in form
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The radical Islamist group made the claim on its Amaq news agency, saying the attacker used a suicide vest in the strike Wednesday, which targeted a classroom packed with teenagers in a Shiite Muslim district of the Afghan capital.
Ghani's visit came hours after U.S. Defense Secretary Jim Mattis said the situation in Ghazni has become "much more stable" since most Taliban fighters withdrew to the outskirts of the city.
Security forces were on patrol and no militants were in sight in the centre of the shattered city, with fighting seeming to have ceased.
Afghan president Ashraf Ghani is visiting the embattled city of Ghazni, a week after the Taliban in a surprise attack managed to infiltrate deep into the key provincial capital and capture several areas.
"Death and hatred to this government and filthy terrorist that everyday they are killing innocent Afghans", he added. That gives the government a strong incentive to build on recent, tentative signs that diplomatic efforts to kick-start peace negotiations are starting to bear fruit, he said. "For the insurgents, the thinking is, "why quit when we're ahead"?"
AT least 88 civilians and security personnel have been killed in two separate terror attacks. Afghanistan in recent times has witnessed an unusual surge in violence triggered by the Taliban. "Today, even in Kabul, people may be starting to fear a sudden attack by the Taliban against the city".