The customs authorities are increasing vigil on rivers routes to Bangladesh in and around the Sunderbans to prevent smuggling, officials said on Tuesday.

The marine vessels and the crew, which were earlier based in Calcutta, have been redeployed to Hemnagar (North 24-Parganas), Namkhana (South 24-Parganas) and Haldia (East Midnapore).

At least 14 such vessels, including those which can go into the high seas, have been redeployed, a customs officer said.

“Large amounts of cargo, including fly ash and heavy machineries, are carried on barges through the rivers from Bengal to Bangladesh. We have decided to increase vigil on the river routes and have redeployed our vessels,” Deep Sekhar, principal commissioner of customs, said.

Recently, customs officers had seized 100 gold biscuits from a vessel coming from Bangladesh.

At Banashyam Nagar, in the Ramganga area of the Sunderbans in South 24-Parganas, officers chased a trawler and seized 539 packets of garments, apparently headed to Bangladesh illegally.

The goods were valued at Rs 4.7 crore approximately, a customs officer said.

“Small high-speed vessels are effective for chasing while the bigger ones can go even into the high seas,” principal commissioner Sekhar said.

The marine preventive unit of the customs will undertake patrolling the riverine routes in and around the Sunderbans and around Sandhead, Henri Island and Jammu Dwip.

The vessels based at Hemnagar will keep a watch along the rivers in Basirhat, Hasnabad and Hingalganj, along the India-Bangladesh border.

The crew will check vessels entering and leaving India, the officer said. Several bridges are being built in Bangladesh, for which heavy machinery are being taken through river routes.

Roads leading to the Bangladesh border are, at places, too narrow to accommodate vehicles carrying such heavy machinery.