Boko haram extremists attack Nigeria
Boko Haram extremists, shown here, have started seizing territory in a shift in strategy  YouTube

The Nigerian terror group Boko Haram has implemented Sharia law in the town of Gwoza, beheading Christian men in the area and forcing their wives into marriage with the group's members, according to local media reports.

The barbaric actions of the Islamist militants, against the town's Christian population, were revealed by Gideon Obasogie, the Director of Social Communications of the Catholic Diocese of Maiduguri, the capital of Borno State.

In a statement to reporters, he confirmed that Christian men were beheaded for not converting to Islam.

"Christian men were caught and beheaded, the women were forced to become Muslims and were taken as wives to the terrorists," he said.

"A lot of church structures have been burnt. Christians in the town are really in a terrible situation. Their houses are now occupied by Boko Haram.

"It is quite clear that terrorism has no friend, but it is abundantly clear that the Christians are worst- hit," he added.

Andrew Noakes, Coordinator of the Nigeria Security Network (NSN), said that while these tactics were not new, the group now have the "resources, confidence and organisational capacity" to extend their control beyond the rural areas and into towns such as Gwoza.

"Boko Haram have a long history of attacking Christians, carrying out beheadings, and forcing women to convert to Islam and marry militants. Indeed, the Chibok girls are believed to have been converted and forced into marriage," he said.

Reports of beheadings conjure thoughts of Isis (now known as the Islamic State) and their march through northern Iraq and northeastern Syria. Noakes says that there are clear parallels between the tactics employed by Boko Haram and those used by the Islamic State.

"There are similarities between the way Boko Haram and Isis have made lightning gains, rapidly seizing territory and threatening major population centres. There are also similarities between their treatment of Christians and captured soldiers. We know that Boko Haram have pledged their support for Isis."

Three northern states - Borno, Yobe and Adamawa - have been under a state of emergency since May 2013 as the group's insurgency continues to blight Jonathan Goodluck's administration.

Attacks attributed to the group have occurred in northern cities such as Maiduguri and Kano but their reach has started to expand southwards, with bomb blasts striking the Middle Belt cities of Jos and the capital Abuja.

Earlier this year, the group kidnapped more than 200 schoolgirls in the village of Chibok, bringing global attention to the west African nation's fight against terrorism.

According to Human Rights Watch, Boko Haram has killed at least 2,053 people since the beginning of 2014.