KANO - Nigerian troops were on Thursday accused of killing 16 Boko Haram suspects, after vigilantes claimed to have beheaded dozens of Islamist fighters in the country's far northeast.
Boko Haram was meanwhile reported to have begun enforcing strict Islamic law by amputating the hands of thieves and razing churches in a captured town it renamed as part of its self-styled caliphate.
And 21 civilians were killed after Boko Haram fighters clashed with troops in the restive northeast of Nigeria on Wednesday, a local lawmaker said on Thursday.
The incidents raised fresh concern about the conduct of the military and the civilians supporting it and undermined repeated government claims of a ceasefire and peace talks.
In Potiskum, 16 men who were arrested after morning prayers on Wednesday were found dead in a morgue with bullet wounds just hours later, community leaders and hospital staff told AFP.
Locals in the Dogo Tebo area of the city believed the men were picked up and killed because all of them were from the Kanuri ethnic group that forms the bulk of Boko Haram's membership.
"All the bodies have gunshot wounds on them," said a nurse at the Potiskum General Hospital, who asked not to be identified because he was not authorised to speak to the media.
The bodies had been brought in by soldiers and were formally identified by community leaders, he told AFP.
On Monday, at least 15 people were killed and some 50 others were injured in a suicide bombing targeting a major Shia Muslim festival in Potiskum, which is Yobe state's commercial capital.
A number of others were killed when troops deployed to the scene opened fire, the head of the Shia community, Mustapha Lawan Nasidi, said at the time.
The latest deaths were described by another community leader as "cold-blooded murder" while residents expressed concern about the fate of a Muslim cleric and three others who were also detained.
Neither the military in Yobe or the capital, Abuja, responded to AFP when asked for comment and there was no word either on claims from Biu in neighbouring Borno state about the beheadings.
A member of the civilian vigilante group, Umar Hassan, said they and troops ambushed Boko Haram fighters last Friday as they prepared a raid on Sabon Gari village in the south of the state.
"We killed 41 of them and decapitated them and brought the heads to Biu, which we displayed to people to demystify Boko Haram," he said.
Two Biu residents said the vigilantes put the heads on wooden spikes and drove around the town, telling people the Islamists did not have magical powers.
"It was like hunters displaying their game after a hunting expedition," said, one, Silas Buba.
The incidents will add to concerns of human rights groups about the response of the military and the vigilantes, both of whom have been accused of atrocities in the past.
Amnesty International and Human Rights Watch (HRW) said they were aware of the reports and were investigating the authenticity of the claims.
"This is the latest in a string of abuses in which pro-government vigilante groups have been implicated," said HRW's Nigeria researcher Mausi Segun.
Boko Haram took over the town of Mubi in Adamawa state last week and residents who fled the town in recent days said they had now renamed it Maidanatul Islam, or "City of Islam" in Arabic.
In Mubi, Boko Haram chopped off the hands of 10 men accused of theft last Friday and burnt down churches, said Ahmad Maishanu, who fled Mubi on Wednesday.
In a video released on October 2, Boko Haram showed the stoning to death of a man accused of adultery, a man having his right hand cut off for theft and a young man and woman given 100 lashes each for sex outside marriage.
The group, which wants to create a hardline Islamic state in Nigeria's northeast, is now thought to control at least two dozen towns in the region.
The Nigerian government and military made a surprise announcement on October 17 that it had secured a ceasefire deal with the militants and peace talks were being held.
But there has been no let-up in the violence since then and last Friday the group's leader, Abubakar Shekau, dismissed claims of an end to hostilities as "a lie".