Kano (Nigeria) (AFP) - Boko Haram has been forced to produce its own fuel to power its motorbikes because of an acute petrol shortage caused by a military squeeze on supply lines.
A senior military source said the Islamists were paying huge sums of money for jerrycans of fuel while a woman who recently escaped from the group said they were making groundnut oil into biodiesel.
"Boko Haram were paying outrageous sums to get fuel and the incredible profit margin made young men defy the risk and take fuel to them," said the source in the Borno state capital, Maiduguri.
"The cutting off of fuel supplies has badly crippled Boko Haram and that has been made possible by blocking all identified supply routes and the crackdown on the suppliers," he told AFP.
Fuel vendors seeking to exploit the group's need for fuel could sell each 25-litre jerrycan for 50,000 to 70,000 naira ($250-$350, 222-311 euros) each, said escapee Ya-Mairam Ya-Malaye.
A jerrycan of fuel in Maiduguri costs only $13.
But the risk of being caught up in a military aerial bombardment on Boko Haram positions has forced the vendors to stay away, said the security source.
Babakura Kolo, a civilian vigilante assisting the military against the Islamic State group affiliate in Maiduguri, said the militants would pay any amount to get fuel.
"It was a lucrative business for the fuel vendors," said Kolo, who was involved in the crackdown against Boko Haram suppliers in the city.
"But we have taken care of them and Boko Haram are feeling the crunch because they are out of supplies."
Previous reports have indicated the rebels are also running low on food.
- Groundnut oil -
Nigeria and its neighbours Cameroon, Chad and Niger began a concerted fight-back against Boko Haram in January last year, recapturing territory lost to the militants the previous year.
President Muhammadu Buhari has said the rebels, whose insurgency has killed an estimated 20,000 people and forced some 2.6 million to flee since 2009, can no longer fight conventional warfare.
Instead of its trademark hit-and-run attacks using pick-up trucks mounted with heavy machine guns, the insurgents have even mounted strikes on remote villages on horseback, bicycles or on foot.
Ya-Mairam Ya-Malaye, a 57-year-old mother-of-eight who was among hundreds of women and children abducted from the town of Bama in September 2014, managed to escape Boko Haram last week.
She said the group has devised a crude way of adding salt to oil extracted from groundnuts to make biodiesel for their motorcycles to mount attacks from their Sambisa Forest enclaves in Borno.
"They confiscate the groundnuts (that) farmers in villages in and around Sambisa cultivated all-year-round from their farms and irrigation fields," she explained from Maiduguri.
"They crush the nuts using diesel-powered grinding machines to extract the oil to which they add salt to make it light and combustible."
Boko Haram had been getting fuel from young men who would bring the petrol to designated points near Sambisa (forest) for the fighters to pick, she added.
Ya-Malaye said she was taken to Sambisa Forest from Bama and moved between camps as troops pushed further into the former game reserve in pursuit of the militants.
The offensives and heightened border security made it difficult for the militants to receive deliveries from fuel vendors from Maiduguri and Cameroonian border towns, she added.