Staff at a religious school in Pakistan cleared debris and opened hours of worship after a bomb attack on Tuesday that killed eight students.
The explosion in the northwestern city of Peshawar hit the main hall of the madrasa as classes were in progress.
The prayer muezzin said they wanted to show the attackers that they were "not defeated".
No one has claimed attacks in a city long plagued by violent extremism.
The morning explosion occurred as students studied the Koran, killing eight men aged between 20 and 40. In addition, more than 80 other people were injured, many of them children.
Peshawar, near the Afghan border, has in recent years experienced some of the worst violence linked to Taliban insurgencies in both countries.