At least 23 people have been killed in northern Nigeria by gunmen targeting "anti-islamic gamblers" and "forbidden meat traders".

Local officials said the attack on Tuesday was targeted at activities disapproved by armed groups.

Alhaji Abba Ahmed, a local official said an earlier attack, late on Monday, proved to be the deadliest.

Gunmen opened fire at a market in the town of Damboa, targeting local hunters who sell bush meat from animals such as monkeys and pigs - which Muslims are forbidden to eat.

"Gunmen suspected to be members of BH (Boko Haram) came to the town market and shot dead 13 local hunters on the spot while five others died from their injuries at the hospital," Ahmed said.

"They came to the market in a Volkswagen Golf car, carried out the operation and left," he added.

Witnesses said a separate attack took place on Tuesday in the north's biggest city of Kano, about 500km west of Damboa, when suspected Boko Haram members shot dead five people playing an outdoor board game.

A hospital source who received the bodies said that two others had been wounded.

Damboa is in the remote northeast, the Boko Haram's heartland near the borders with Niger, Cameroon and Chad.

Boko Haram's aim is to carve an Islamic state out of Nigeria, a nation of 170 million people almost evenly divided between Christians and Muslims.