After seven years of relative peace, one of the world's most oil-rich regions is once again under siege by militants. And though Nigeria is well-acquainted with violence on its southern shores, the group behind a new wave of attacks — the Niger Delta Avengers — is shrouded in mystery and sabotaging one of the world's biggest oil producers.
The attacks present a serious challenge for President Muhammadu Buhari, who entered office last year in the midst of a global oil price downturn that has plunged Nigeria into economic crisis and stoked runaway inflation. Now, assaults by the Avengers have helped send the country's crude output to its lowest level in decades.
Nigeria is home to Africa's largest economy and one of the world's biggest populations. Before this year's supply disruptions, the OPEC member was also the continent's top crude producer. The oil industry accounts for about 70 percent of government revenue.
The Niger Delta Avengers are in the business of destroying oil infrastructure — working in teams, carrying small arms and explosives, blowing up pipelines and sabotaging facilities — taking advantage of the Delta's complex, creek-filled terrain to stay one step ahead of the Nigerian soldiers chasing them.
They're driven by economic and environmental grievances, and until those issues are addressed, the Delta will remain in a cycle of sabotage, experts told CNBC. And Nigeria's oil output will remain under pressure.
The Avengers claim on their website to be young, educated and well-traveled. They say they are better armed and more civilized than past militants. One thing's for sure: They are making an impact.
Nigerian Oil Minister Emmanuel Ibe Kachikwu this week said the country's oil production has fallen by 800,000 barrels per day — to 1.4 million barrels per day — due to attacks on the nation's infrastructure, local news reported, many or perhaps most of them at the hands of the Avengers.
"We don't see this being a huge group, but at the same time, they do seem very effective," said Matthew Bey, energy and technology analyst at geopolitical research firm Stratfor.
On Wednesday, Italian energy giant Eni confirmed that one of its Nigerian pipelines was sabotaged, UPI reported. The following day, Exxon Mobil said operations at its Qua Iboe oil terminal — Nigeria's largest — had been disrupted by criminal activity. No one has claimed responsibility for those incidents, but the Avengers are high on the suspect list.
The Avengers did claim responsibility for a recent attack on Chevron's Okan offshore platform, Shell's Forcados oil pipeline and other infrastructure. In recent weeks, Shell and Chevron have reportedly evacuated staff.
Chevron declined to comment on evacuations or attacks on installations claimed by the Avengers beyond the Okan platform. Shell said it did not wish to comment on details of its response to recent attacks, adding that its operations are continuing.
The Avengers demand greater ownership of oil resources for the people who live in crude-producing areas. They want environmental repair and compensation for damages inflicted by oil producers. And they want continued government funding for an amnesty program that is largely credited with halting the last round of Delta violence, which mostly ended in 2009.
Experts on the region say it's unclear if The Delta Avengers comprise militants who were active during the last period of unrest — an umbrella group called MEND that operated from 2006 to 2009 — or if they're an entirely new organization.
The Avengers criticize the older groups of militants for kidnapping people, killing Nigerian soldiers and allegedly enriching themselves after the 2009 amnesty program. The older alliance of militants had a diverse group of leaders who contracted out attacks on oil infrastructure. There is so far scant evidence that the Avengers have that same scale, said Stratfor's Bey.
But Bey said the Avengers appear to be attempting to generate solidarity with other parts of the Niger Delta that have historical grievances with oil companies. They claim their members come from different ethnic groups and regions, and have evoked the plight of the Ogoni, whose lands have been ravaged by crude pollution.
"Going forward, Buhari's biggest challenge is making sure this doesn't spread and become a greater movement," Bey said.
This week, another group calling itself the Red Egbesu Water Lions vowed to join the fight if some of the Avengers' demands were not met within a week, local news reported.
If the attacks come at the worst possible time for Nigeria, they were also to be expected. Experts say the amnesty deal was always a short-term solution.
Under the program, the government handed out multimillion-dollar contracts to the top leaders of the last round of militants, paying them to guard oil infrastructure. The rank and file were compensated with stipends and job training.
"Essentially, the amnesty was a massive payoff system," said former U.S. Ambassador to Nigeria John Campbell.
"The leaders of MEND, of the insurrection, were paid off essentially with government contracts. The rank and file were supposed to be paid off with vocational training. Of course, there aren't any jobs in the area," he told CNBC.
Buhari has extended the program through 2017, but he's also reduced payouts, circumvented the former militant leaders who previously distributed them and stopped funding security contracts.
Bearing in mind these changes, Ambassador Campbell said the Avengers could be acting on a "cluster of motivations" that are both selfish and selfless.
The attacks are likely born out of resentment over amnesty payments drying up and an anti-corruption campaign that has disrupted traditional patronage, as well as concern about environmental damage and the long-held belief the Delta region does not get an equitable share of oil revenues, he said.
The structure of the amnesty also offers clues about the Avengers' makeup.
Midlevel commanders were left without opportunities that matched their expectations and sense of their own standing, said Akin Iwilade, a research student at Oxford University who studies why Nigerians join gangs and has interacted with former militants.
"Many of these guys, they got into the amnesty, but they didn't get half of what they expected," he said, though he cautioned there is no hard evidence to suggest the Avengers are comprised of former midlevel commanders.
While the amnesty failed to address broader concerns about development and political inclusion, Iwilade said it has improved the lives of former low-level militants by allowing fugitives to return to civilian life and reducing violence in the Delta. And while training has failed to lead to jobs in many cases, it has allowed at least some people to start businesses and families, he said.
Those benefits could limit the appeal among former militants of returning to the Delta's networks of creeks to carry out attacks.
Still, the Nigerian government runs the risk of exacerbating the problem if it takes a hard line, said Olanshile Akintola, another research student at Oxford who also interacts with Nigerian youth, told CNBC in a separate interview.
"What we're really concerned about is Buhari's response to the NDA has been one of serious threats, which historically hasn't worked. It's just made things worse," he said.
Buhari has vowed to stamp out the Avengers, but the military has found it difficult in the past to hunt down militants in the Delta's maze of creeks. Nigeria's armed forces are also stretched thin as they wage a simultaneous, separate campaign against Muslim terror group Boko Haram in the north, and grapples with ethnic land conflicts in Nigeria's middle belt.
Both Iwilade and Akintola said the ultimate solution will require Buhari to start a dialogue with the Delta region and address the root causes of unrest.
The key is to show a greater commitment to a more-inclusive form of government that reduces marginalization and assures Buhari's anti-corruption campaign does not solely target the opposition party, Iwilade said.
Until then, the amnesty has given young, disenfranchised men a simple model, according to Ambassador Campbell.
"If you have nothing to do, go out, blow up enough and you'll get bought off," he said.