They were nabbed from the Maheshkhali channel of the Bay of Bengal around 12 am on Saturday, said Commander Lt Colonel Khairul Islam Sarkar of RAB-15 in Cox’s Bazar.
The detainees could not be identified immediately.
Acting on a tip-off, members of the elite police unit headed out to sea on a fishing trawler in the guise of fishermen around 9 pm, said Khairul.
A group of suspicious people were spotted in a trawler at midnight, he said. “Afterwards, RAB laid siege to the trawler and detained six people. Three guns and 11 bullets were also seized from the trawler.”
The arrestees have confessed to carrying out robberies at sea for a long time during interrogation, he said.
Preparations are underway to file a case against them at Cox’s Bazar Sadar Police Station.