Nigeria's Delta region is home to vast oil reserves, which make the country one of the world's biggest oil exporters.
But the region remains poor, undeveloped and riven by conflict.
Analysts say the region is 'awash with weapons'
For many years, armed gangs of youths, who hide out in the swamps and creeks that make up the Delta, have attacked oil pipelines and kidnapped foreign workers for ransom.
A recent report commissioned by Shell said the level of conflict in the region was comparable to Colombia and Chechnya.
Attacks on Shell installations have forced a 10% drop in Nigeria's oil production.
Many of the armed groups claim to support impoverished local communities and say the oil belongs to the Delta people in the first place.
Oil tankers stolen
"The Niger Delta is awash with weapons," Prof George Frynas, a specialist in Nigeria's oil industry, told the BBC's World Today programme.
He says the weapons have been bought from the proceeds of kidnapping oil workers, selling oil they steal from pipelines and that some have been distributed by politicians at election time.
Some of the strongest allegations of electoral fraud from the last elections came from the Niger Delta.
Local human rights activists said that in some areas, armed men had turned up at polling stations and calmly made off with the ballot boxes, which they proceeded to stuff.
Another specialist on Nigeria, Anthony Goldman, says the scale of the attacks and the vast quantities of oil being siphoned confirms that senior Nigerian officials have protected and backed the armed militia that operate in the Niger Delta.
In some cases, huge oil tankers - mostly from the former Soviet Union - have been used to carry away the stolen oil to foreign markets.
Two Nigerian rear admirals were court-martialled last year for their part in the attempted theft of thousands of tons of Nigerian oil by an international crime syndicate operating in Russia and eastern Europe.
'Too little, too late'
Although troops have been deployed to try to restore order, they are frequently outgunned by the militia.
Analysts say the military can do little without parallel efforts to tackle the roots of the problem.
Prof Frynas, from Middlesex University in the UK, says it is unlikely that oil companies will pull out of Nigeria but they have already started to move to off-shore oil fields, which are further from population centres and so less vulnerable to attack.
"Nigeria will still be a big producer of oil but people will not venture into villages - it is just too dangerous."
Over the past few decades the population of Nigeria has grown rapidly but despite the country's vast oil wealth, the large majority of the population have continued getting poorer.
In order to raise living standards in the region, the government and oil companies have set up the Niger Delta Development Commission.
This is supposed to use oil money to improve the region's infrastructure, such as schools and health clinics and to create jobs.
But Prof Frynas says it seems to be "too little, too late".
"A lot of the efforts have been bogged down in corruption and inefficiency. Still very little money has trickled down to the people."