Dhaka, Jun 29 (IANS): At least 21 people have died in devastating flash floods and landslides triggered by heavy rains that lashed southeastern hilly districts of Bangladesh, officials said on Sunday.

Tens of thousands of people were marooned on higher ground as flood waters submerged areas around Cox's Bazar and the hilly district of Bandarban, Xinhua reported.

Police confirmed that 21 bodies were recovered from a river on Sunday.

In 2012, at least 88 people were killed in devastating landslides caused by heavy rains in Bangladesh's two southeastern districts, Cox's Bazaar and Bandarban.

Earlier in June 2007, some 123 people were killed in a devastating landslide in Bangladesh's southeastern Chittagong district.

Bangladesh - one of the world's most densely populated countries - is highly vulnerable to natural disasters, including cyclones, droughts, floods and earthquakes.

India, Bangladesh and China are most at risk from river floods, with an increasing number of people threatened because of climate change and economic growth in low-lying regions, a study said in March.