Foreign mercenaries, primarily from South Africa, are reportedly assisting the Nigerian military in their fight against terrorist group Boko Haram, which is now officially allied to the Islamic State (ISIS/ISIL).

According to various media reports, hundreds of foreign mercenaries have poured into Nigeria.

The foreigners, mainly from South Africa, are “playing a decisive role in Nigeria’s military campaign against Boko Haram, operating attack helicopters and armored personnel carriers and fighting to retake towns and villages captured by the Islamist militant group, according to senior officials in the region,” reports The New York Times (NYT).

Mike Omeri, a spokesman for the Nigerian government, told BBC that the foreigners were in Nigeria to train the African country’s forces.

Nigerian President Goodluck Jonathan told Voice of America that two security companies were providing “trainers and technicians” to help the Nigerian military. He did not elaborate further.

Nevertheless, the South African government is reportedly concerned about its nationals working as mercenaries in Nigeria’s war against Boko Haram.

“South Africa has issued strong warnings against any mercenary activities in Nigeria, saying that any of its citizens fighting there would be prosecuted upon returning to South Africa,” reports NYT. 

On condition of anonymity, a Western diplomat told The Times that the South Africans were playing “a major operational role,” particularly during the night.

The mercenaries “are whacking them in the evening hours,” said the diplomat.

An unnamed “American source” with ties to Nigerian security officials told Foreign Policy (FP) that Nigeria “turned to South African defense contractors to provide helicopters and pilots.”

“That happened after the United States refused to provide weapons and blocked the sale of Cobra attack helicopters from Israel to Nigeria,” reports FP.

The South African mercenaries have been linked to members of the apartheid-era military, namely the now-defunct Executive Outcomes group.

“They’re relics of apartheid,” Jakkie Cilliers, executive director of the Institute for Security Studies in Pretoria, told NYT. “They love this gung-ho kind of stuff, and they’re good at it.”

“It’s not the best of options for a nation to compromise her sovereignty by bringing in mercenaries,” a senior Nigerian government official said to The Times on condition of anonymity. “But if talking to the devil is necessary, it’s worth the price.”

The NYT article notes that mercenaries from former Soviet republics may have also joined the Nigerian military’s fight against Boko Haram.

Thousands have been killed since Boko Haram began its reign of terror in 2009. The jihadist group seeks to establish an Islamic state in the Nigerian region.

ISIS has accepted Boko Haram’s pledge of allegiance, making it an official branch of the Syria/Iraq-based terrorist group.

Boko Haram has been officially labeled a terrorist organization by the United States.