Manpura, Tazumuddin, Daulatkhan of Bhola and Dhal Char of Noakhali in last two days.

Pirates also hijacked 17 trawlers, abducted 42 fishermen and injured another 50.

Two notorious pirates gangs popularly known as Speaker and Jahangir Bahini hijacked the trawler FB Jalchhabi at Manpura at 5:00pm Saturday afternoon.

They also picked up two of the crew -- Khokan and Siddik -- and demanded Tk 2 lakh in ransom.

At Tajumuddin, pirates looted four trawlers where the fishermen held two of the pirates. At least 20 pirate trawlers rushed to the spot to rescue their comrades and went on a piracy spree.

On information, a police patrol of Manpura Police Station rushed to the spot and engaged into a clash with the pirates near Dhal Char.

Reinforcements were sent from Tazumuddin and Daulatkhan Police Stations and the gunfight continued till 2:00am Sunday.

Police fired more than 40 gunshots. At one point, the pirate gangs retreated and fled to Char Mozammel of Noakhali.

Police seized 12 trawlers abandoned by the pirates, of which seven were hijacked. Police operation is going on in the region to recover the abducted fishermen and hijacked trawlers, police sources said.