Bangladeshi authorities on Monday warned millions of people living along the coast that a brewing cyclone was gathering strength and could barrel into their homes later this week.
The Bangladesh Meteorological Department raised its warning level about cyclonic storm MAHASEN to four, meaning "there are increased chances that the cyclone will hit the coast", its deputy head Shamsuddin Ahmed told AFP.
Mr Ahmed said that Mahasen was currently in the Bay of Bengal, 1,355 kilometres (840 miles) south west of the second city of Chittagong, and could make landfall in the southeast of the country on Thursday.
"MAHASEN is still a cyclonic storm. It has not gathered enough strength to become a severe cyclone. But it is likely to intensify further," he said.
The government has made preparations for the cyclone, but will wait until it has firmer information as to where it would make landfall before issuing any evacuation order, Chittagong provincial administrator Muhammad Abdullah said.
"We've alerted the people living in coastal areas, but have not evacuated any of them because we still don't know where the cyclone will hit. But we're fully prepared to face any situation," he told AFP.
He said authorities have readied logistics support and kept cyclone preparedness volunteers, doctors and officials ready for the cyclone.
Around 30 million of Bangladesh's population of 153 million live along the coast.
Bangladesh has been a frequent victim of cyclones which have left hundreds of thousands of people dead since independence in 1971.
The last time a major storm hit Bangladesh was in May 2009 when Cyclone Aila slammed into southern Bangladesh, killing about 300, and triggering a huge tidal wave that destroyed river embankments and left hundreds homeless.
In November 2007 Cyclone Sidr hit southern Bangladesh, killing at least 4,000 people.