Insurgency in the north-east has led the president to impose a state of emergency that oppresses residents stuck in the middle.
As the paved roads of north-eastern Nigeria begin to melt into the sands of the Sahara desert, a cluster of picture-perfect mud-and-thatch homes marks the entrance into Boko Haram territory. Here, barely 30 minutes' drive from the neat government complexes flanked by fountains and tamarind trees in Borno state's capital, Maiduguri, power slips almost entirely into the hands of the group trying to carve an Islamist state inAfrica's most populous country.
"They walk around here holding their guns as if they are carrying just ordinary bottles of water," said Garba, an old man laying out bundles of straw in the blazing sun. He waved at the horizon where goats and camels grazed on scrubby bushes. "That is where they bury [their guns] in the sand."
"You shouldn't stay long – they kill anyone they don't know here," he added.
The increasing infiltration of far-flung settlements such as this, dotted along a route that leads into hideouts in the vast Sahara that spans porous borders, prompted Nigeria's president, Goodluck Jonathan, on Tuesday to impose a state of emergency on the north-eastern states of Borno, Yobe and Adamawa. "In many places, they have destroyed the Nigerian flag and other symbols of state authority and in their place, hoisted strange flags suggesting the exercise of alternative sovereignty," he said during the televised announcement.
Around 8,000 troops will be granted sweeping powers in an attempt to crush the insurgency militarily, a move that could inflame tensions with local communities and is likely to mean pulling some Nigerian troops from the west African-led force battling a separate Islamist insurgency in Mali.
Chris Olukolade, the national defence spokesman, said the bulk of military action would focus on border communities.
Bolstered by sophisticated weapons from Libya, The Guardian has learned Boko Haram is trying to strengthen its hold through chilling new tactics that include forcible conscription.
Indigo-robed men on camels ride past cars rusting on the side of the explosive-ridden road. The windows of government health centres have been blasted out, and bullet holes scar the weed-covered signposts of schools. Yards away from the remains of a camel protruding from the sand, a cluster of children in bright rags sit under the shade of a neem tree, carefully copying their lessons onto chalkboards in an almajari, or Qur'anic school.
In the dust-blown city of Maiduguri, where the group's secretive membership has thrown a cloak of suspicion over entire neighbourhoods, civilians gathered in nervous knots to watch troops pouring in.
"I see plenty of soldiers moving in with their trucks chanting their war songs, but they are just going in there to kill innocent citizens," said resident Abba Kakami. "What happens if soldiers meet farmers who carry [traditional hunting] guns? How can they differentiate between a terrorist and a civilian?"
Just off the main roads where cars are forced to brake suddenly at barked orders from policemen behind sandbags, residents have long barricaded their own side streets against the security forces in a city that appears at war with itself.
"Boko Haram are the kings of these streets," said Hamza, grilling sticks of meat in an otherwise deserted street in London Chiki, a neighbourhood scarred with burnt out homes. With a nervous glance over his shoulder where a nearby notice threatened to kill any informants, he said: "What do the security forces expect us to do in this situation? You keep quiet before [Boko Haram] send you to your grave."
Weakened by a military crackdown and brutal internal codes that have seen members peel away to form splinter groups, Boko Haram commanders have also turned to ruthless new methods as they attempt to stage a comeback.
In the past, most captured operatives cited jihad and promises of paradise during interrogations, security officials and two locals in regular contact with Boko Haram cells told the Guardian. Now they increasingly give a disturbing new motive: they have been ordered to kill or be killed themselves.
"They told us members assigned to 'high-value areas' must get a 'hit' within two weeks, or their own commanders kill them," said a senior intelligence official who interrogates suspects in the northern capital, Kano. "It doesn't matter who they kill; they have to kill to stay alive."
Among the earliest to experience this was Kano-based mechanic Chuku, who found himself sharing a jail cell with 17 militants last year after failing to scrape together a police bribe. "They talked about the Qur'an and said soon Nigeria would be an Islamic state," Chuku said, talking quietly in a dust-covered liquor store of the kind targeted by the insurgents.
Peering anxiously into the streets, where turbaned guardsmen on horseback, living ghosts of Kano's empire glory days, rode past patrolling police tanks, he said: "They told me not to worry because some of their guys were going to get us out of this jail."
When an explosion rocked the jail cell a week later, an attack which left 185 dead, his cell occupants started cheering. As Chuku made to escape the grounds strewn with bodies, two men grabbed him and sniffed his clothes to make sure he wasn't a police officer – those held in police cells are almost never allowed to wash or change clothes – then led him to a Peugeot van. "The boot was full of AK47s with barrels sawn off. They told me I must take one, and kill a policeman or they will kill me," Chuku said.
He took a gun and escaped from the men in the chaos of the battle.
Nigerian troops also face a group who appear to have a new military edge after gaining control of weapons from Libya. In Bama this month, a co-ordinated strike against a police station army barracks left 55 dead and freed over 100. "They came in with around 20 pickup trucks, around half of them were mounted with anti-aircraft guns," said a policeman who was present during the attacks. "This is a weapon that can bring down a commercial jet. As soon as you fire one of those things, nobody knows what is happening."
Analysts say emergency rule could weaken urban cells, but questions remain as to what happens once the six-month emergency rule is lifted. "The growing militarisation of the north-east will provide short-term gains, but will fail to address the root drivers of militancy," Control Risks Africa analyst Roddy Barclay said.