At least four suspected pirates were killed in a gunfight with police at Uttar Dhal Char in Monpura upazila, Bhola, early Sunday, according to a UNB report.
The district police superintendent Maniruzzaman said a gang of pirates had opened fire on a patrol team from Lalmohan police station in the area around 2:30am.
Police also fired at the pirates, triggering a gunfight that lasted for an hour, leaving four pirates dead on the spot.
At one stage, the pirates fled the scene with the bodies of their unidentified cohorts.
Police later seized a trawler used by the pirates.