The Taliban hung on in Ghazni for almost five days before USA -backed Afghan forces flushed them out in what were some of the fiercest battles with the insurgents in recent months that killed scores of Afghan troops and civilians. The blast left the floor strewn with twisted metal, broken desks and human limbs.
The Hazara have often been targeted by the hardline Sunni Islamic State militant group.
No group immediately claimed responsibility for the attack but Jawad Ghawari, a member of the city's Shiite clerical council, blamed IS, which has carried similar attacks on Shiites in the past, hitting mosques, schools and cultural centers.
Afghan President Ashraf Ghani has also condemned the "terrorist" attack on the Shiites that "martyred and wounded the innocent" - students attending class - and ordered an investigation to determine how the bomber had managed to sneak into the compound, which has its own guards. The secretary claimed Taliban fighters had targeted six locations, but failed to seize any. It also comes as USA and Afghan forces intensify ground and air offensives against the Islamic State, and the Taliban step up their turf war with the group.
The militants said about 110 people were either killed or wounded in Thursday's attack that began in the morning.
In the past two years, there have been at least 13 attacks on the Shiite community in Kabul alone.
Partial solar eclipse on August 11
The next total solar Eclipse will occur July 2, 2019 and will be visible to people in the South Pacific and South America. An eclipse should not be seen with the naked eye, maintains NASA as it can cause damage to the eye.
"The bomber detonated himself inside the education centre", police spokesman Hashmat Stanikzai said.
Authorities meanwhile revised the death toll from Wednesday's bombing in Kabul's neighborhood of Dasht-e-Barchi to 34 killed, not 48.
The president held talks with senior security officials and governor of Ghazni who was reportedly out of the country when the city came under attack last Friday.
Afghan government's Chief Executive Officer Abdullah Abdullah confirmed last month, in the first official reaction, that a meeting had taken place between the US and the Taliban to initiate the peace process. For two days we had no water and no food.
Militant attacks and suicide bombs were the leading causes of civilian deaths in the first half of 2018, a recent United Nations report showed.
Zabihullah Mujahid, the Taliban spokesman, was quick to deny any involvement by the insurgents in the attack. "Reliable information indicates that the Ghazni Public Hospital is overwhelmed by a continuous influx of injured government forces, Taliban fighters and civilians".
A week into the offensive, however, Afghan forces were still busy clearing areas around the city and along the highway in the province, where rebels were still fighting with the security forces.