The gangs frequently attack the cargo vessels anchoring there, sources said.

They posed a threat to the security of the cargo ships calling at Chittagong port to carry import and export goods.

A senior port official on condition of anonymity said the cargo vessels were facing frequent incidents of piracy and theft at the outer anchorage for the past two months.

"But affected vessel operators hardly lodge complaints with police fearing further attacks," he added.

The pirates attacked a local coaster vessel named 'Barvina' recently and looted goods worth Tk 10 lakh after keeping the crew members hostage at gunpoint.

Meanwhile, Chittagong Port Authority (CPA) held a high powered meeting early this month against the backdrop of incidents of piracy and theft on the vessels calling here, port sources said.

Senior officials from port, shipping, navy, police, coast guards, ansars and representatives from shipping agents association and other port users attended the meeting.

The meeting decided to take prompt measures to curb piracy at the port channel, jetties and outer anchorage in order to ensure safety and security to the vessels calling at Chittagong port.

CPA Chairman Shahadat Hossain said, "we have intensified patrolling at the outer anchorage and port areas to check attacks on ships and as a result, the situation is under control now.

"But sometimes, we get information of attacks on ships beyond our port limit area," Shahadat said.

"We are very much careful to ensure safety and security of the vessels calling here as any untoward incident can create image problem for our port," he said.

The CPA chairman said regular patrolling at the outer anchorage was stepped up with the help of navy and coastguards.

Navy source said a patrol ship was engaged to keep watch over the outer anchorage regularly.

The coastguards also patrol at the outer anchorage to check the acts of pirates and other miscreants.

The coastguards recently in a drive at the outer anchorage caught 12 people along with their unauthorised boats.

The shipping agents were advised to take members of ansars to ships at the outer anchorage for security. But shipping agents avoid hiring of ansars as they find it costly, port sources said.

Bangladesh Shipping Agents Association (BSAA) Chairman Farid Ahmed Chowdhury said, "it will be very expensive to afford ansars on board the vessels. That is why we are not taking ansars to the vessels. Instead, we engage some watchmen on the vessels for security purpose".

" We think that if proper surveillance can be ensured at the outer anchorage by the coastguards and Navy, the vessels will hardly come under attacks from pirates there," he said.

Cutting of ropes from most of the ships at the time of anchorage at port area is a common phenomenon. Some organised rope dealers in the city reportedly maintain clandestine links with the pirate groups to get the supply of ropes, sources said.

CPA Deputy Director (Security) Lokman Hossain said a high speed boat was procured this month to intensify patrolling in the river Karnaphuli to check piracy and pilferage.

Besides, some other patrol boats were engaged for the purpose to ensure safety and security in and around the port, Lokman added.