Boko Haram militants have beheaded four internally displaced people in northeastern Nigeria on Saturday ( 20 May), local media reported. The victims were decapitated as they were hunting outside the Dalori camp in Maiduguri, capital of restive Borno state, the Premium Times reported.

The victims were part of a 12-men-strong hunting group. Six of them managed to return to the camp, while another two are still believed to be missing, witnesses said.

The victims were buried on Sunday by their fellow displaced people. The men were believed to be volunteer members of a vigilante group, the civilian joint task force ( CJTF), which helps the Nigerian military in the fight against Boko Haram.

"We have severally warned them going even 2km kilometres away from their camps in that axis is very dangerous because the Boko Haram insurgents were there in the bush. But they refused to heed to warning, by insisting on going to hunt in the bush," the leader of the CJTF, Abba Kalli, said.

Borno is Boko Haram's birthplace and the epicentre of the group's insurgency. At least 501,000 people were displaced by the group in 2016, according to the 2017 Global Report on Internal Displacement.

Boko Haram fights against Western influence in Nigeria and aims to impose its version of Sharia law throughout occupied territories. The Islamist outfit is affiliated to the Isis terror group.

The United Nations says at least 20,000 people have died in Nigeria and neighbouring states since the Boko Haram insurgency became violent in 2009. The conflict has also displaced at least 2.1 million people.

Boko Haram is renowned for kidnapping civilians, particularly women and children, and forcing them to carry out suicide bombing missions.

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Earlier in May, the group released 82 girls in exchange for prisoners following negotiations that involved also the Swiss government.

Those freed were part of a group of more than 200 schoolgirls kidnapped from the Chibok village, in Borno, in April 2014.

Although the Chibok abduction was not the first mass-kidnapping carried out by Boko Haram, it was the only one that attracted international outrage. It led to the creation of the global movement Bring Back Our Girls, which shone a spotlight on the deadly insurgency of Boko Haram that had previously been underreported.

Boko Haram used to control territories the size of Belgium. However, Nigeria's ongoing military operation, Lafiya Dole, and a regional offensive – consisting of 8,700 troops from Nigeria, Niger, Chad, Cameroon and Benin – have scored some success, with soldiers recapturing key territories and releasing thousands of civilians held captive by the group.

However, on 13 May, a purported Boko Haram fighter was reported to have released a video claiming that the militant group had been planning to carry out several bomb attacks in the Nigerian capital, Abuja.

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