Nearly 50 people have been killed in Nigeria in an attack by militant Islamist group Boko Haram on a group of fish traders, a union leader says.

The head of the fish traders association said the incident happened in Nigeria’s restive Borno State.

• US extends Afghanistan role
• 28 dead in Kenya bus attack

“Scores of Boko Haram fighters blocked a route linking Nigeria with Chad near the fishing village of Doron Baga on the shores of Lake Chad on Thursday and killed a group of 48 fish traders on their way to Chad to buy fish,” Abubakar Gamandi said.

He said the insurgents set up a barricade at Dogon Fili, 15 kilometres from Doron Baga, and stopped a convoy of fish vendors about midday.

“The Boko Haram gunmen slit the throats of some of the men and tied the hands and legs of the others before throwing them into the lake to drown,” Mr Gamandi said.

Boko Haram was responsible for the kidnap of 276 schoolgirls in the Nigerian town of Chibok more than six months ago.

Fifty-seven of the students managed to escape but talks aimed at securing the release of the rest of the group are at an impasse.