* Five days of heaviest rain in years
* Downpours cause floods, landslides
* Hundreds of homes washed away (Updates death toll, adds details)
By Anis Ahmed
DHAKA, June 27 (Reuters) - At least 100 people have died and 250,000 left stranded by flash floods and landslides in Bangladesh set off by the heaviest rain in years, police and officials said on Wednesday.
The low-lying and densely populated country, which is in its wet season, has been battered by five days of torrential downpours.
The deaths took place late on Tuesday and on Wednesday. Most were caused by landslides, others by wall collapses, lightning strikes and surges of floodwater. Army, police and fire brigade personnel were helping in rescue efforts.
Weather officials said more rain was expected over the next few days.
Hundreds of homes have been washed away, while authorities have moved many families from shanty housing and told others to leave quickly.
At least 23 people were killed in and around the southeastern port city of Chittagong, while 36 died in Bandarban in an area known as the Chittagong Hill Tracts.
"Several more people are feared trapped in hillside homes buried under heaps of mud. Rescue operations are continuing," Chittagong Deputy Commissioner Faiz Ahmed said.
A further 38 died in the coastal district of Cox's Bazar near the Myanmar border, officials and police said.
Officials in the affected areas said about 100 people were missing, many swept away by floodwater, and about 200 injured.
In Sylhet, a rice and tea-growing area in the northeast, houses were filled by up to three feet (one metre) of floodwater, and residents were forced to perch on boats or scramble to high ground. Three children were reported killed.
Flooding also hit districts northwest of the capital Dhaka.
The downpours lashed the borders with Myanmar and India, with the weather office recording 463 mm (18.2 inches) in Chittagong over the past 24 hours.
"We are having the worst rainfall in many years," said Jainul Bari, district commissioner for Cox's Bazar.
Disaster control officials said about 150,000 people had been marooned by the floods in the southeast while 50,000 were stranded in Sylhet.
About 50,000 were reported stranded in their flooded homes in the northern districts of Gaibandha and Kurigram.
Local television showed villagers trudging through waist-high water to relief camps while some moved their cattle on to the roofs of buildings for safety.
Farming officials said it was too early to gauge crop damage. "In flash floods, water recedes soon after the rain stops, so we don't anticipate any major damage to rice and other crops," one official said.
Most road and rail links between Chittagong and the rest of the country were suspended late on Tuesday, while Chittagong airport was closed after part of the runway was flooded.
Authorities have started distributing food, drinking water and medicine among survivors. "The government has allocated about 750 tonnes of rice and 6.6 million taka ($80,500) for the affected people," Atiqur Rahman, a senior disaster ministry official, said. (Additional reporting by Ruma Paul, Nurul Islam in COX'S BAZAR and Raju Ahmed in SYLHET; Editing by Pravin Char)