Cyclone Nargis over the southwest Bay of Bengal and adjoining southeast Bay has intensified into a severe cyclone, according to a special weather bulletin issued Tuesday., reports bdnews24.com.

The cyclone was centred about 1170km southwest of Chittagong port, 1110km southwest of Cox's Bazar port and 1050km south-southwest of Mongla port Tuesday.

It is likely to intensify further and move northwards, the Meteorological Department said in the bulletin. The maximum sustained wind speed within 90km of the storm centre is about 64km per hour rising to 115km per hour in gusts or squalls.

The sea will remain rough over the north Bay and "very rough" near the cyclone centre. Maritime ports of Chittagong, Cox's Bazar and Mongla have been asked to keep hoisted the distant warning signal 2, the bulletin said.

All fishing boats and trawlers over the north Bay have been asked to stay near the coast and proceed with caution until further notice. They have been advised not to go to the deep sea.