The elite Rapid Action Battalion conducted a raid at Shahebjan Alis home in Tanores Bilsahar village based on a tip, bdnews24 reported.
The detainees have been identified as Shahebjan Ali, 35, Abul Kalam Azad, 28, and Jahangir Alam, 28.
RAB-5 Commander Lt Col Mohammad Mahbubul Alam said that they seized 500 gram of gunpowder, seven extremist propaganda leaflets and bomb-making material from their possession.
The home was searched, the three were detained and the bomb-making materials were seized, Alam said.
RAB officials say the three are part of banned Islamic terror outfit Jamaat-ul-Mujahideen Bangladesh.