Over 18 million people in Bangladesh have been affected by severe monsoon conditions, with more than 1.2 million families trapped as flash floods submerge vast areas of the country’s east and southeast.

The worst affected regions are Chattogram and Sylhet, where major rivers are “flowing well above danger levels”, further aggravating the situation, according to the UN Children’s Fund (UNICEF).

Initial estimates suggest that around five million people – including two million children – have been affected, many stranded without food and relief.

Twenty deaths have been reported as of Tuesday, and a further 285,000 have sought refuge in more than 3,500 shelters, UNICEF added.

Massive damage has also been reported to roads, croplands, and fisheries, severely impacting livelihoods.

Government-led search and rescue operations are ongoing, with some areas inaccessible.

UN-partners in some places have reported that water levels are not expected to recede for at least a week, with risk of persistent waterlogging and accompanying threat of water- and vector-borne diseases.