Flash floods triggered by incessant rains have left at least 27 people dead and nearly six lakh others marooned in nearly two dozen districts in Bangladesh, officials said on Monday.

The unrelenting flow of water from upstream regions coupled with monsoon rains has flooded as many as 20 districts with the flooding spreading to other parts, officials said.

The Disaster Management Ministry said that 27 people have died in the floods as monsoon grasped 20 of the country’s 64 administrative districts.

The deluge has affected some 586,000 people, forcing 368,586 of them to take refuge in makeshift shelters as the country witnesses the second round of floods since June.

Disaster Management Minister Mofazzal Hossain Chowdhury said that government’s preparedness was underway to face a greater disaster in view of severe flooding in upstream countries like, China, India, Nepal and Bhutan.

“We have been carefully monitoring the situation in those countries [as] the water will naturally flow downstream to us,” he said.

His comments came as expert feared the deluge to engulf vast part of the riverine nation in the coming weeks, causing a prolonged flooding.

The Flood Forecasting and Warning Centre (FFWC) records suggest that water levels in three out of four river basins were rising simultaneously.

If there are more rains at the end of August, at least 25 districts will be affected by floods, the FFWC predicted.

The water levels will keep rising as India’s northeastern states will see “heavy to very heavy” rains, it said.

“We are taking all precautionary measures keeping the forecast in mind,” Department of Disaster Management Director General Reaz Ahmed said.

Around 60,000 families in Kurigram and at least 400 families in Nilphamari have been marooned.

Railway officials said train services in several internal routes remain suspended for the past two days as water washed away soil and stones underneath the railway tracks.

Onrush of waters in the major Brahmaputra river and its tributaries coupled with heavy monsoon rains in the district submerged railway tracks forcing authorities to suspend train services in Dinajpur district.

“All indicators suggest that the flood is likely to be severe this time,” leading water expert Professor Ainun Nishat told PTI.

Prof. Nishat said gushing waters from three sides of the upstream region were heading towards central Bangladesh and feared that the unprotected eastern part Dhaka could be submerged for a prolonged period.

“The full moon phenomenon is to worsen the situation coinciding with the bursting water level but all we need to do is to protect in particular the flood protection embankments which are in place to evade damage as much as possible,” Prof. Nishat said.

Prime Minister Sheikh Hasina on Sunday ordered procurement of food grains from abroad to face any possible shortfall against the backdrop of impending deluge.

Bangladesh witnessed a setback in crop production two months ago when a prolonged flash flood washed away standing crops in north-eastern region.

TV footages showed people were moving in boats in northern districts as swollen river waters inundated flood plains and submerged infrastructures.

The FFWC officials said the water level in the Brahmaputra river, having its origin in China and entering Bangladesh from India, exceeded the records of past 100 years.

It said that continued and simultaneous rise of waters in the three major basins in the northeast, north and northwest regions posed the threat of major flooding in lower riparian Bangladesh criss-crossed by 230 rivers, 54 major ones being originated from upstream India.

The Teesta basin water level also surpassed the 98 years record and the rest of the three basins — the Ganges — this year saw the highest level of waters in the past 75 years.

The Water Development Board said the level of water rose at 77 of its 90 observation points.

Bangladesh experienced the worst floods in decades in 1998 when 68 per cent areas of the country submerged. The flooding in 2007 was less severe than those of 1988 and 1998, affecting 40 per cent of the country.