Members of Rapid Action Battalion (RAB) arrested three suspected members of Ansarullah Bangla Team (ABT) from Rupganj upazila on Friday night.
The arrestees are identified as Rezaur Rahman, 27, Abu Raihan, 28 and Mobarak Hossain, 33.
UNB said RAB also recovered arms, bullet, jihadi books and leaflet from their possession.
The details will be revealed at a press briefing.