Gunmen have opened fire on a crowd of cinema-goers in northern Nigeria, killing at least 11 people and injuring more than 20 others, witnesses and hospital sources have told the BBC.

The attack by suspected bandits happened on Wednesday night in north-western Zamfara state.

Eyewitnesses say the attackers arrived in the village of Badarawa on foot. They then headed to the village hall, known as a viewing centre, where residents gather at night to watch films or football.

When gunmen opened fire, the cinema-goers panicked, running for safety - most escaping with either multiple gunshot wounds or broken bones.

Hospital sources say some of the injuries are life-threatening.

The dead have already been buried.

It is not clear why the cinema was targeted but villages in Zamfara have been coming under deadly attack by armed bandits in recent months.

The rights group Amnesty International said in a recent report that nearly 400 people had been killed in the state since the beginning of this year.

The police say security personnel have been deployed to track down the most recent assailants.

There are growing concerns about security in Nigeria - Africa's most populous country - ahead of general elections in February.