At least 32 people have been killed in a gun battle between security forces and a radical Islamist group in north-east Nigeria, reports say.

Dozens of people attacked a police station in Bauchi city but were repelled, Reuters news agency said.

The agency quoted a police spokesman as saying the militants belonged to Boko Haram, a group seeking the imposition of sharia law across Nigeria.

Islamic law has been in effect in the state of Bauchi since 2001.

AFP news agency quoted a hospital nurse, Awwal Isa, as saying that as many as 42 people had been killed in Sunday's clashes.

One of the dead was a soldier, he said.

Dozens of people were also reported to have been injured.

The police spokesman, Mohammed Barau, said the situation had been brought under control and that members of the gang were being detained.

One gang member, who gave his name as Abdullah, told Reuters the group had retaliated because authorities had been arresting its leaders.

The man was also quoted as saying that the group wanted to "clean the [Nigerian] system which is polluted by Western education and uphold sharia all over the country".

In February, Bauchi was the scene of clashes between Muslim and Christian communities, which left four people dead.

Nigeria's 140 million people are split almost equally between Muslims and Christians and the two groups generally live peacefully side by side.