Islamist group Boko Haram has begun taking over churches in the areas of Nigeria where it has gained control, beheading men and forcing women to convert to Islam, according to local reports.

The extremist group is turning churches into strategic bases, according to local Christians. Local news agencies report that it is also imposing strict sharia law, beheading Christian men, forcing conversions and living in the homes of people who have fled. 

"Things are getting pretty bad," Rev John Bakeni, the secretary of the Maiduguri Roman Catholic diocese, told the Religion News Service. "A good number of our parishes in Pulka and Madagali areas have been overrun in the last few days.

"Many civilians are now on the run," he added. "Many others are being trapped and killed. Life means nothing here. It's so cheap and valueless."

Local newspapers report that "every Christian man available in the areas" has been beheaded.

This week Boko Haram seized another town, Bama, in Northern Nigeria, with just a handful of fighters, following their advances in the region and their declaration that they have founded a new Islamic Caliphate. As many as 5,000 people have fled the town, and scores were killed in the fighting. 

However Amnesty International has released footage which it says shows Nigerian soldiers putting Boko Haram suspects into a mass grave.

Boko Haram has also kidnapped hundreds of children who have yet to be found. In the past few years, the group has repeatedly attacked churches and exploded bombs in Nigeria.

James Duddridge, the Minister for Africa, attended a meeting in Abuja today to discuss regional coordination in the fight against Boko Haram.

Speaking this morning ahead of the meeting he said:

"Boko Haram is a growing threat to peace and stability in the region, and regional coordination between Nigeria and its neighbours remains crucial to defeating the extremists and locating the missing Chibok girls.

"In London, the UK announced a substantial package of military, security and development assistance. I will be updating partners on the significant progress made on implementation of this package, whilst underlining that respect for human rights and safeguarding the civilian population remain the key pillars of our support.

"Most importantly, with our French, US and other international partners, we will today again reiterate our common stance that we cannot, and will not, tolerate Boko Haram's brutal and inhumane crimes."