At least 51 people were killed after a boat sank in Nigeria's northwestern Sokoto state Thursday, as rescue teams continued searching the waters for victims and possible survivors, according to local accounts.

Such accidents are common on Nigeria's busy rivers and waterways, often caused by overloaded boats, poor maintenance or failure to comply with safety regulations.

Scores of people drown each year.

"The situation is bad," said Ibrahim Musa, a former councillor of Gorau village, in Goronyo district, where the accident occurred.

"We already buried 46 bodies, and five others have just been brought out of the river."

Ilyasu Adamu, a local farmer, said the boat was "obviously overloaded", adding that it had sunk just a minute after starting its journey.

"The passengers were heading to the farm on the other side of the river. Most of them were women and children. Some of the girls were to get married soon," he told AFP, giving a toll of at least 48.

Dahir Kure, spokesman for the National Emergency Management Agency in the state, told AFP, said rescue operations were underway.

"We are now at the scene of the boat accident and have begun rescue work," Kure said.

Kure said he could not immediately give a toll, saying authorities were still "collecting necessary information on the incident".

At least five people drowned when a boat capsized in Jigawa state last month.

In January, at least 26 people drowned when a boat carrying farmers and fishermen from Jigawa to Yobe state capsized.