More than 30 people are feared dead after a ferry collided with a barge south of the Bangladeshi capital, and rescuers have begun retrieving bodies, officials said.

The double-decker Shariatpur 1 ferry was hit on Tuesday early morning by another vessel in the middle of the Meghna River southeast of Dhaka, Shahidul Islam, a local police official, told AFP news agency.

"About 35 passengers were rescued by another ferry. But more than 150 passengers remain unaccounted for," Islam said. The vessel was thought to have been carrying about 200 people, although the exact number is unknown.

Divers had so far recovered more than 30 bodies from inside the sunken ferry, local police official Mohammad Shahabuddin Khan told the Associated Press.

"The death toll is likely to rise as more bodies are feared trapped inside," Khan said. "We will get a better picture of the casualties once the sunken ferry is pulled out of the water."

Hundreds of anxious people, many of them weeping, gathered near the scene of the accident, in Munshiganj district, about 32km south of Dhaka, to look for loved ones who were on board the ferry.

Al Jazeera's Nicolas Haque, reporting from near the scene of the accident, described "a sea of grieving people" waiting to get word about the status of their loved ones.

"One by one rescuers are bringing out bodies. I have seen bodies of children, women and there is a crowd of people here crying and it's quite an astonishing scene here at the edge of the river," Haque said.

'Big jolt'

Dulal Dewan, a survivor, described a scene of chaos as the ferry collided with the other ship.

"I was awakened with a big jolt," said the businessman, who was asleep on the top deck. "I jumped into the river in darkness as the ferry started going down."

"In minutes there were screams all around," he said. "People were shouting for help."

Dewan said he was rescued by a nearby boat, but eight other family members travelling with him were still unaccounted for.

Coastguards, fire brigade and police rescue workers rushed to the site after the accident at 2:30am local time (20:30 GMT Monday).

Ferry accidents, often blamed on overcrowding, faulty vessels and lax rules, are common in Bangladesh, a low-lying delta nation of 160 million people.

In April last year 32 people were killed after a passenger vessel sank in the Meghna river after colliding with a cargo ship.