One of the men accused of responsibility for Nigeria's Christmas Day bombings, which killed dozens, has been arrested, security sources say.

Habibu Bama, a former soldier, was shot during his arrest in the north-eastern city of Damaturu, the sources say.

He is accused of being a member of the Boko Haram Islamist group, which has killed hundreds of people.

On Thursday, the US state department designated three Boko Haram leaders as terrorists.

Mr Bama, is believed to have masterminded the December 2011 attacks on a church near the capital, Abuja, as well as previous attacks on the UN headquarters and a military base, security sources have told the BBC.

In January, Kabiru Sokoto, another suspect in the Christmas Day bombings escaped from custody before being recaptured the following month.

His escape last month was a huge embarrassment for the police, whose leading officer was sacked shortly afterwards.

The security sources say Mr Bama was declared a wanted man shortly after Mr Sokoto was arrested.

'Religious cleansing'

The three Boko Haram leaders designated as terrorists are: Abubakar Shekau; Abubakar Adam Kambar and Khalid el Barnawi.

The move means any assets belonging to the men in the US will be frozen, and contact with US citizens banned.

More than 100 people have been killed this week in bombings, revenge attacks and gun battles in Damaturu and Kaduna.

Attacks on churches in Kaduna on Sunday, sparked reprisals against members of the Muslim community.