Up to 150 people drowned in a river or were shot dead fleeing Boko Haram gunmen who raided a remote village in Nigeria's northeastern Yobe state, locals said on Tuesday.

Dozens of militants arrived on motorcycles and a car on Thursday last week and opened fire, scattering terrified residents of Kukuwa-Gari.

"They opened fire instantly, which forced residents to flee. They shot a number of people. Unfortunately many residents who tried to flee plunged into the river which is full from the rain. Many drowned," Modu Balumi, a resident of the village told AFP.

"By our latest toll we have 150 people either (shot dead) or drowned in the attack. The gunmen deliberately killed a fisherman who tried to save drowning residents of the village."

Balumi said the bodies of many of the drowned were picked out by locals several kilometres away.

News of the attack was slow to emerge because the militants have destroyed telecom masts around the village, around 50 kilometres (30 miles) from Yobe State capital Damaturu, since the insurgency began in 2009.

"Boko Haram gunmen attacked our village on Thursday which led to the deaths of around 150 people. Most of the victims died in the river while trying to escape. The gunmen opened fire on the village forcing people to run to safety," Bukar Tijjani, another villager, told AFP.

"Most residents, particularly women and children, ran towards the river in confusion. They were pursued by the gunmen, who kept firing at them. In the frantic effort to escape they jumped into the river, which was full to the brim."

A local government official confirmed the attack but put the death toll much lower, at around 50.