The Counter Terrorism and Transnational Crime (CTTC) unit of police arrested Shamin Mahfuj, founder of militant group Jama'atul Ansar Fil Hindal Sharqiya, and his wife from Demra in the capital on Friday night.
A huge cache of explosives was recovered from their possession, said DMP Additional Commissioner of Police (CTTC) Md Asaduzzaman.
A press briefing on the incident will be held at DMP media center on Saturday noon.
Leaders of three militant outfits formed Jama'atul Ansar Fil Hindal Sharqiya in 2019.
Shamin had been a key figure in the outfit since its formation, the CTTC official said.
