The joint forces detained three members of the armed group Kuki-Chin National Front (KNF) in Ruma upazila of Bandarban on Sunday night.
Among them, one was directly involved in recent bank robberies, said Saikat Shahin, superintendent of the district police (SP).
He said the law enforcers also held a driver along with a vehicle used in the bank robberies in Thanchi upazila.
The SP also said four armoured vehicles were brought to the district for use in the ongoing joint drive against the Kuki-Chin.
Earlier yesterday, the Rapid Action Battalion (RAB) arrested KNF chief coordinator Cheosim Bom, 55, in a drive conducted in Sualok area in Sadar upazila of Bandarban.
BSS adds: The members of the armed group Kuki-Chin National Front (KNF) recently attacked the Ruma Upazila Parishad office, tried to rob Sonali Bank's Ruma Branch in Bandarban, and abducted its manager Nezam Uddin.
Later, the KNF members looted two branches of Krishi and Sonali banks located in Thanchi Bazar area in Thanchi upazila on Wednesday.
Thanchi UNO Md Mamun confirmed the incident, saying, "About 15-20 people went inside the bank branches and took Tk 17.45 lakh apart from mobile phones."
Nayan Chakrabarty/MSU