Boko Haram is conducting its campaign of terror in the northeast corner of Nigeria and neighboring Cameroon on the cheap, making mayhem with a makeshift collection of small arms, automatic weapons, rifles, rocket- propelled grenades and mortars, experts on the turbulent region say.
Most of the Islamic terror group's weapons are either stolen from Nigerian military stocks or purchased on the thriving Central African arms black market, say the experts, including current and former U.S. officials.
The group blamed for last month's kidnapping of nearly 300 Nigerian schoolgirls routinely raids police stations and military bases in search of weapons, they say. In some cases, Boko Haram sympathizers in the Nigerian military abet the theft.
"There are hints that sympathizers in the Nigerian army will leave doors of armories unlocked for Boko Haram," said John Campbell, U.S. ambassador to Nigeria from 2004 to 2007.
In addition to weapons, the rebels frequently seize non-lethal equipment that helps them carry out their terror attacks, said one U.S. official, citing a raid last week on an open market in northeast Nigeria that left 310 people dead. That attack, according to local reports, was carried out by men in Nigerian military uniforms who arrived in Nigerian military armored personnel carriers.
Apart from benefiting from sympathizers in the Nigerian military, the Islamic terror group is able to purchase small arms and occasionally some larger weaponry in nearby conflict zones, "probably Libya, probably Chad," said the official, who spoke with NBC News on condition of anonymity.
However, these arms are not being acquired systematically from other militant groups - including al Qaeda and its African affiliates -- but through "shady, black market" arrangements across barely marked borders, as the official put it.
Michael Leiter, former director of the National Counter Terrorism Center and now an NBC News analyst, says Central Africa is brimming with the weapons, a situation made worse when the Libyan arms depots were looted during the 2011 Arab Spring.
"The collapse of Libya has further flooded the market," said Leiter. "Whether these came from Chad, Nigeria, or Libya is almost irrelevant, as such arms are widely available."
Arms trade expert William M. Hartung agrees. "It's one conflict after another," he said. "Because of the nature of the conflict … the concentration of conflicts … the black market in Central Africa is more vibrant than other places."
Campbell, the former U.S. ambassador to Nigeria, says the array of small and automatic weapons, grenades, mortars, mines and perhaps car bombs "is all (Boko Haram's soldiers) need to carry out their brand of terrorism."
Officials in Cameroon on Tuesday showed reporters, including NBC News' Stephanie Gosk, a cache of weapons they said was seized near the Nigerian border last month following a rescue of some other kidnapping victims. A Cameroon defense ministry spokesman said the cache represents what they are up against on a daily basis in trying to combat Boko Haram, showing off a variety of weaponry including Russian-made AK-47s.
U.S. officials, Leiter and Campbell all dismiss the idea that Al Qaeda or its African affiliates are supplying Boko Haram with weapons.
"We'd caution against the notion that any significant quantity of weapons would be provided by AQ," either Al Qaeda Central or Al Qaeda in the Islamic Magreb, said one U.S. official.
Leiter notes there has been reporting that Al Qaeda in the Islamic Maghreb has provided Boko Haram fighters with some training since 2009 - a period that coincides with the latter's adoption of "aggressive and sophisticated attacks."
"It is hard to say this is a causal relationship, but these are the sorts of concerns such engagement produces," he said.
Hartung, now director of the Arms and Security Project at Center for International Policy, says that despite the ubiquity of weapons in Central Africa, there are ways to at least crimp the black market. He points to efforts by the United Nations to stem the arms trade in southern Africa a decade ago.
"The problem is that there hasn't been (a recent effort) to shut down the networks," said Hartung. "The U.N. did some good research tracking how guns get to conflict zones around 2000. There were marking and tracing efforts for guns and bullets, efforts to track financial transactions. Now that's gone, so even the naming and shaming aspect hasn't been happening."