It's a country of around 185 million people, a member of OPEC and the biggest economy on its continent. But Nigeria may have more than it can handle with the "Niger Delta Avengers."

Soldiers from the 7th Division of the Nigerian Army on March 25, 2016. Stefan Heunis | AFP | Getty Images

Nigeria has vowed to rein in the militants who are relentlessly bombing the country's oil infrastructure and have slashed its crude output. But experts say the government of President Muhammadu Buhari lacks the military capacity and institutions to tackle the threat — and military action could make things much worse anyway.

Little is certain about the motives of the Niger Delta Avengers. But the group claims through its website and Twitter feed that it wants a bigger share of the Niger Delta's resource wealth to go to the region's people, and it wants some sort of environmental remediation after decades of rampant oil and gas pollution. What is certain is that the Avengers are effective. Nigeria's oil production has fallen from 2.2 million barrels per day to roughly 1.6 million after a spate of attacks, which come as the country was already in crisis mode thanks to a rout in global oil prices.

It's not like an insurgency in the classic sense ... If they find these guys and hunt them down and shoot them, there will be another group the next day. Gerald McLoughlin former U.S. foreign service officer

Nigeria has deployed more troops to the delta and begun talks with state and local leaders to address their grievances. This week, Nigerian Oil Minister Emmanuel Ibe Kachikwu called on the Avengers to "sheath their weapons and embrace dialogue with the government."

The Avengers responded in their Twitter feed: "We're not negotiating with any committee. If Fed Govt is discussing with any group they're doing that on their own."

The Nigerian military has slim hopes of finding and defeating the militant group in the delta's swampy network of creeks, say experts. The terrain confounded soldiers during a prior, yearslong campaign against oil militants, who stopped bombing oil installations only after the government began paying them as part of a 2009 amnesty program. "I think it would be very difficult to tackle this issue using essentially police methods," said John Campbell, former U.S. ambassador to Nigeria. "The delta doesn't lend itself to military or police action, and in fact, it failed the last time there was an insurrection there."

The military, which Buhari is trying to remake into a more professional fighting force, also has little support among delta residents, and its presence could make matters worse, according to Campbell. Abuse of civilians at the hands of the military in northern Nigeria provided a potent recruitment tool for Boko Haram, Campbell said. That group has gone on to become one of the world's most deadly terrorist organizations. If similar abuses were repeated in the delta, more militants would likely emerge, he said. This week, the federal government said it would withdraw troops from villages after complaints of heavy-handed tactics. Meanwhile, the Avengers have at least tacit support from some locals in the delta. Members are viewed as part bandit and part Al Capone, but they are also seen as part Robin Hood, said Gerald McLoughlin, an independent analyst and former U.S. foreign service officer with experience in Nigeria. That sympathy, coupled with a lack of economic opportunity in the delta, make the group extremely difficult to combat.

"Quite frankly, it's almost impossible. It's not like an insurgency in the classic sense," he told CNBC. "If they find these guys and hunt them down and shoot them, there will be another group the next day. What else can you do if you live there?" he said.

Winning hearts and minds

Nigeria President Muhammadu Buhari Frank Augstein | Pool | Reuters

The Buhari government could conceivably build goodwill by embarking on public works projects, said Ambassador Cambell. Construction of a long-discussed road across the delta region, for example, would employ a huge number of workers and open new areas to economic development, provided it functioned well.

The delta ostensibly has institutions in place to execute such projects, but they have accomplished little, said Manji Cheto, senior vice president at advisory firm Teneo Intelligence. The Niger Delta Development Commission was founded in 2000, followed by the Niger Delta Ministry in 2008. There is also an office dedicated to carrying out the 2009 amnesty program. The organizations carry out programs, but have no cohesive blueprint for development, and much of their funding falls into a "black hole," Cheto said. The government should merge the three organizations, she said. "Quite clearly they didn't see this as a priority. Now, with pipelines being attacked every week, it has to become a priority," she said.

Analysts don't doubt that Buhari is committed to the anti-corruption crusade he campaigned on, but they say his hands are tied by corruption at the state and local level, where oil revenue that's distributed by the federal government is frequently misallocated.

"What happens in many cases is the funds arrive on the state governor's desk and there's no further accounting for them," Ambassador Campbell said. "The state legislatures are supposed to hold the governors accountable, but very often, the legislatures are part of the (patronage) network controlled by governors." That system makes delta people skeptical that talks between federal and local leaders will produce change, Cheto said.

Fear of an independent delta

Beyond the impact on the Nigerian economy, the Avengers could agitate separatist sentiment in the delta — a potentially disastrous development in a country like Nigeria with divided regional, tribal and religious loyalties.

Cheto said she's concerned about increased activity among independence groups in the south's Biafra region. The delta state fought a devastating civil war with Nigeria from 1967 to 1970. At the peak of that conflict, Nigeria's total blockade of Biafra led to thousands of deaths by starvation on a daily basis.

Broken pipework sits at an abandoned oil flow station operated by Royal Dutch Shell Plc in K-Dare, Nigeria, Jan. 13, 2016. George Osodi | Bloomberg | Getty Images