Dhaka, Dec. 27 -- An explosion ripped through a madrasa in the Hasnabad area of South Keraniganj, Dhaka, on Friday morning, injuring four people, including a woman and two children, police said.

The blast occurred around 10:30 am at a single-storey building of Ummal Qura International Madrasa, blowing off the walls of two rooms on the western side. Witnesses and police reported finding cocktails, chemicals and various bomb-making materials at the scene, as per local media reports.

Officer-in-Charge Saiful Alam of South Keraniganj Police Station said a bomb disposal unit and a crime scene team were working at the site to determine the cause of the explosion. A general diary has been filed, and the operation was ongoing.

Those injured we...