At least 40 people have drowned and are presumed to have died after their boat capsized on a river in northwest Nigeria, officials say.

The wooden boat was ferrying more than 50 farmers to their fields across the river near Gummi town in Zamfara state on Saturday when it capsized, a local official said on Sunday.

“Only 12 were rescued yesterday shortly after the accident,” said Na’Allah Musa, a political administrator of the flood-hit Gummi district where the accident happened, adding that authorities were searching for the bodies of the rest of the passengers.

Musa added that the vessel was “crammed with passengers far beyond its capacity, which caused it to overturn and sink”.

“This is the second time such an incident has occurred in the Gummi local government area,” Aminu Nuhu Falale, a local administrator who led the rescue efforts, told Reuters news agency.

More than 900 farmers rely on crossing the river in the region daily to access their farmlands. But only two boats are available, often leading to overcrowding, Falale added.

In a statement on Sunday, Nigeria’s President Bola Tinubu “expressed the government and the people of Nigeria’s commiseration” for the “twin tragedies” of the farmers’ deaths and the nearby floods.

In recent days, rising waters in the Gummi area have forced more than 10,000 people to flee, with Tinubu promising support for the victims.

Zamfara state is also rampant with armed groups who kidnap for ransom, steal cattle and engage in illegal mining.

Boat accidents are common on Nigeria’s poorly regulated waterways, particularly during the rainy season when rivers and lakes swell. Locals say most boats don’t carry life jackets or have proper safety measures in place.

Last month, nearly 30 farmers on their way to their rice fields drowned after their overloaded boat sank in the Dundaye River in neighbouring Sokoto state, emergency officials said.

Three days earlier, 15 farmers died when their canoe overturned on the Gamoda River in Jigawa state, according to the police.