During the raid on a house, the elite police unit arrested four JMB activists, including a regional chief of the banned group.
RAB's media wing Director Mufti Mahmud Khan said a huge quantity of weapons, ammunition and bomb-making material have been recovered from the house.
The house belonged to one Jesmin Akhtar, he added.
Among the four JMB activists arrested was one Mahmudul Hassan Tanvir, the ‘Amir’ of the group's southern region, the RAB spokesperson said.
The other three have been identified as Ashiqul Akbar Abesh, Najmus Shakib and Rahmatullah Shuvo.
Khan said these four had taken shelter in this house before Eid during Ramadan and that the house was used for training JMB recruits.
Security forces have been looking for JMB hideouts and raiding them since the Gulshan cafe and Sholakia terror strikes, for which Bangladesh intelligence agencies have blamed the JMB.