MAIDUGURI, Nigeria (AP) — The battered old car, cutlasses and nail-studded clubs poking out of its windows, careens down the road and squeals to a stop. Its young occupants pile out, shouting with glee, and set up a roadblock.
"Get down!" ''Open the trunk!" ''What's in that parcel?" They yell as a line of stopped cars and minivan taxis forms that will become nearly two kilometers (a mile) long.
They are part of a vigilante force that has arisen here as a backlash against Boko Haram, the Islamic extremist network responsible for 1,700 deaths in Nigeria since 2010, according to a count by The Associated Press.
They call themselves the "Civilian Joint Task Force" and claim credit for thousands of arrests in Maiduguri, where Boko Haram started.
Many residents welcome the vigilantes and credit them for some of the relative peace that has returned to Maiduguri. Others find their existence troubling and worry that they may perpetrate human rights abuses.
"Boko Haram has no mercy for us, so we have no mercy for them," Usman Adamu, 30, told AP.
The vigilantes' emergence over the past six weeks reflects the twists and turns the battle against Islamic extremist violence is taking in Africa's most populous country, where the 160 million people are divided about equally between Muslims and Christians.
Many vigilante recruits are themselves Muslims — an indication that Boko Haram's appeal is far from universal. Officials say the extremists have killed more Muslims than Christians. Though Christians started the first vigilante groups, they have quickly become outnumbered by Muslims equally afraid of the extremists.
On Sunday, suspected Boko Haram attackers crept into a mosque in Konduga town, 35 kilometers (22 miles) from Maiduguri, and gunned down 47 people, the local chief told the AP. In an apparent simultaneous attack on a village 5 kilometers (3 miles) outside the city, another 12 civilians were killed, he said.
Boko Haram has attacked other mosques and Muslim clerics who criticize its actions as un-Islamic.
The vigilantes have won the blessing of the military, and take their name from the military Joint Task Force charged with hunting down the Islamic extremists.
Garba Madu, a middle-aged chief of the civilian force in this city's Moduganari neighborhood, said the movement was well qualified to take on Boko Haram.
"We know who these people are because they have been terrorizing us for years, so we are best placed to sniff them out," he said. "For the past five years we have been under serious attack: Our wives, younger brothers and other family members have been killed."
He said his group had arrested three suspected Boko Haram members in the immediate environs and "countless others" elsewhere.
The civilian movement is growing and expanding into other towns, with military encouragement. Madu, the vigilantes' neighborhood chief, said the military gave the recruits food and juices to celebrate Eid al-Fitr, and the governor of Borno state, where Maiduguri is located, gave a civilian task force commander a shopping bag full of cash for the holiday.
At some checkpoints, the vigilantes are on the road while soldiers keep an eye on them from behind sandbags.
The vigilantes are supposed to hand over suspects to the military or police. But that does not always happen and there are fears they kill some suspects.
"We cannot arrest until we confirm (that they are Boko Haram). We cannot kill until we confirm," said recruit Elias Idriss.
Some worry that the vigilantes may carry out extrajudicial killings and other abuses.
"It's a double-edged sword," said Shehu Sani, head of the Civil Rights Congress of Nigeria based in the northern city of Kaduna.
"On the one side it could be seen as a people's resistance to terrorism and on the other side it could be seen as a proxy force used by the army and the government to prosecute the war on terror and commit heinous human rights violations to which actors cannot be traced and can act with impunity."
Sani warned that other youth organizations created by politicians and the military have "turned into uncontrollable monsters."
Asked about fears that the rise of the Civilian Joint Task Force will lead to abuses, Zanna Mustapha, deputy governor of Borno state, noted that the vigilante group "has been welcomed by everyone including the military and the government."
He said authorities are aware of abuses, such as the burning down of a senior politician's home. The vigilantes acted after the military refused to arrest him, saying they had no evidence he was supporting Boko Haram.
"We had to call in their leaders and talk to them, and they agreed what they had done was not right," Mustapha said, adding the vigilantes are "much more organized now."
Asked about indications they have also killed suspects, Mustapha suggested this was not surprising in a country where a suspected thief can be lynched.
"The simple issue is terrorists," he said. "It is not acceptable, but these Boko Haram, they will not spare you, they will kill you, and those who are now arresting them feel that if you find someone with arms ... " With that, he threw up his hands to suggest that anything could happen.