A gang of armed robbers has killed 23 people in two villages in northern Nigeria, witnesses and police say.

An eyewitness told the BBC that about 80 people on motorbikes launched an overnight attack in the remote villages of Dan-Gulbi and Guru in Zamfara state.

Some victims had their throat cut, according to reports.

The attack is believed to be in revenge for the killing of a suspected group of armed robbers by villagers and vigilante groups last year.

A policeman was said to be among the dead, who were primarily from the village of Dan-Gulbi.

"They went door-to-door shooting villagers and in some cases slitting their throats with knives," an anonymous police source told the AFP news agency.

When do we hear Good news about Nigeria ?