Bangladesh warned millions of people Monday that a cyclone could barrel into their coastal homes later this week as authorities in Myanmar began moving potential victims to higher ground.

The Bangladesh Meteorological Department said that while it was too soon to predict where cyclonic storm Mahasen would hit, it raised its alert to four, meaning "there are increased chances that the cyclone will hit the coast".

The department's deputy head Shamsuddin Ahmed said Mahasen was currently in the Bay of Bengal, 1,355 kilometres (840 miles) south west 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 told AFP.

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 set up 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, and Chittagong is the country's second largest city.

Monday's warning from Bangladesh echoed a similar alert from Myanmar's Department of Meteorology and Hydrology at the weekend.

Myanmar has begun moving people living in tents in flood-prone camps in the western state of Rakhine to wooden shelters or higher ground in preparation for the cyclone.

But some of the roughly 140,000 internally displaced peoples -- mostly Rohingya Muslims made homeless by religious violence last year -- are refusing to move far, according to local officials.

"The authorities asked them to move higher to Muslim villages around their camps. But they didn't want to leave," said a police official in the state capital Sittwe who did not want to be named.

"So refugees living in the makeshift tents moved to newly built wooden huts. The wooden huts cannot be safe for them if the cyclone hits," he added.

An IDP at Bawdupa camp near Sittwe told AFP by telephone that people there were choosing to stay in the wooden shelters.

"The authorities asked us to move to higher ground since yesterday. We didn't go to the villages but are staying in wooden huts near our tents," he said.

Bangladesh and Myanmar have both been frequent victims of cyclones which have left hundreds of thousands of people dead in recent decades.

Cyclone Nargis, which devastated Myanmar's Irrawaddy Delta in May 2008, killed about 140,000 people.

In November 2007 Cyclone Sidr hit southern Bangladesh, killing at least 4,000 people.