At least 37 people died in an inferno on an overcrowded night ferry in Bangladesh on Friday, with terrified passengers leaping overboard and dozens including children still unaccounted for.

The latest maritime tragedy to hit the impoverished low-lying nation saw a fire burn through the three-storey vessel in the early hours while passengers slept on board.

“The three-storey Obhijan 10 caught fire mid-river. We have recovered 37 bodies. The death toll may rise. Most died from the fire and a few by drowning after they jumped into the river,” local police chief Moinul Islam told AFP.

The incident happened early in the morning near the southern rural town of Jhalakathi, 250 kilometres south of the capital Dhaka. The vessel was carrying around 500 people.

Islam said the fire was believed to have originated in the engine room and then ripped through the ferry packed with people returning home from Dhaka.

“We have sent some 100 people with burn injuries to the hospitals in Barisal,” he said.

'Allah save them'

Witnesses said the fire originated at around 3am and quickly spread.

“We were sleeping on a mat on the ground floor deck. All the passengers were sleeping. My nine-year-old grandson, Nayeem, was with me, he jumped into the river. I don't know what happened to him,” said an elderly grandmother.

Other survivors said they saw a small fire in the engine room as soon as the packed ferry set off from the Sadarghat river station in Dhaka at 9pm on Thursday.

“A lot of people ran for safety as the fire spread. A lot of people could not get out of their cabins where they were sleeping. Many jumped into the river,” said another survivor at Barisal Medical College Hospital.

Mohammad Ismail, 48, said that he threw his mother overboard into the “very cold” river and dragged her to the shore, but when he returned on a fishing boat his wife and daughter were nowhere to be seen.

“I saw a person burning in flames,” he told AFP by phone. “My other daughter survived after someone threw her in the river.”

“My father, me, my six-month-old nephew and my sister were travelling together. When the fire broke, I gave the baby to a man. He was trying to save the baby. But now we cannot find them,” one woman survivor said.

As light broke, rescue workers combed through the still-smoking and charred remains of the vessel, removing dead bodies wrapped in white plastic as distraught relatives waited on the muddy riverbank for news.

Johar Ali, the local district administrator, said rescuers arrived at the scene within an hour after the fire broke out and rushed the injured to nearby hospitals.

“We spoke to passengers. And they said there were between 500 and 700 passengers,” he told AFP.

“The fire went on for four or five hours before it was doused. The entire [ferry] has been gutted. But they managed to bring it to the shore,” Ali said.

Local television showed images of burnt motorcycles and gutted cabins inside the boat.

Shell-shocked survivors and their relatives crowded the shore as fire service and coast guard divers scoured the muddy waters.

“I have just found the body of my mother in law. She jumped in the river and died of drowning. I don't know what happened to my wife and children,” said Mohammad Russell from the riverbank near Jhalkathi.

“I searched the hospital. My wife and children weren't there. I hope they survived by jumping into the river. Oh, Allah, save them,” he told AFP.

Pakistan extends condolences

Later, Pakistan offered condolences to the bereaved families and the Bangladesh government over the tragic incident.

"The government and people of Pakistan are deeply saddened by the loss of precious lives in a ferry accident in the Jhalakathi district of Bangladesh. Our deepest condolences to the bereaved families and the government of Bangladesh," said a statement issued by Pakistan's Foreign Office.

"At this moment of grief, our thoughts and prayers are with the ... people of Bangladesh," it added.

String of similar incidents

The accident was the latest in a string of similar incidents in the delta country crisscrossed by rivers.

Experts in the South Asian nation of 170 million people blame poor maintenance, lax safety standards at shipyards and overcrowding.

Fires are also a regular source of tragedy. In July, 52 people perished in a blaze in a food and beverage factory in Rupganj, an industrial town outside Dhaka.

At least 70 people died in February 2019 when a fire tore through Dhaka apartments where chemicals were illegally stored.

In August, at least 21 people were killed when a boat packed with passengers and a sand-laden cargo ship collided in a lake in eastern Bangladesh.

The boat was reportedly carrying some 60 passengers when the cargo ship's steel bow slammed into the other vessel near the town of Bijoynagar.

Divers had to scour more bodies in the murky muddy waters after the cargo ship's steel tip and the boat collided, causing the passenger vessel to capsize.

In April and May, 54 were killed in two separate accidents.

Vessels transporting sand sit low in the water and can be hard to see in choppy conditions, particularly in poor lighting.

In June last year, a ferry sank in Dhaka after it was hit from behind by another ferry, killing at least 32 people.

In February 2015, at least 78 people died when an overcrowded ship collided with a cargo vessel.