A cargo carrying 775 metric tonnes of coal capsized in the Pashur River in Mongla upazila near Sundarbans on Saturday night.
Commander Oli Ullah, harbour master of Mongla Port, said Jashore-bound 'MV-Bilash' capsized in the river around 10:00pm after loading coal from mother vessel MV-Observatory at the port.
The incident occurred as the cargo was following a wrong route and stuck in a hidden char (island), he added.
On information, members of Mongla Coast Guard and the rescue vessel Shib Shah reached the spot and rescued seven staffs including sailors and crews from the capsized vessel, news agency UNB reported citing the Commander.
The authority of the vessel has already been ordered to retrieve the vessel as soon as possible, he added.
Mahmudul Hasan, divisional forest officer (DFO) of Sundarbans East Zone, said the incident spot is very close to the Sundarbans.