LAGOS, Nigeria -- Nigerian troops have arrested a businessman accused of "participating actively" in Boko Haram's mass abduction of nearly 300 schoolgirls from the northeastern town of Chibok last year, Nigeria's Defence Ministry said Tuesday.

Spokesman Maj. Gen. Chris Olukolade said Babuji Ya'ari headed a "terrorists' intelligence cell" for the Islamic extremists while masquerading as a member of the self-defence Youth Vigilante Group. That confirms suspicions that the vigilantes have been infiltrated by Boko Haram. Soldiers have told the AP that some of their comrades also belong to Nigeria's homegrown Islamic extremist group.

"The arrest of the businessman ... has also yielded some vital information and facilitated the arrest of other members of the terrorists' intelligence cell who are women," Olukolade said in a statement Tuesday night. He did not say when the arrests were made or how many people were arrested.

He alleged that Ya'ari has since 2011 co-ordinated several deadly attacks on the northeastern city of Maiduguri, the birthplace of Boko Haram, and spearheaded the May 2014 assassination of the emir of Gwoza, a religious and traditional ruler who was targeted for speaking out against Boko Haram's extremism.

One arrested woman, Hafsat Bako, confessed to co-ordinating the payroll for operatives paid a minimum of 10,000 naira (about $50) a job, the defence ministry statement said.

Boko Haram was responsible for the April 2014 kidnapping of 273 girls from a boarding school in Chibok. Dozens escaped but 219 schoolgirls remain missing. The mass abduction sparked international outrage and demands for the girls' release under the Twitter hashtag .BringBackOurGirls.

The extremists last year took control of a large swath of northeastern Nigeria where they declared an Islamic caliphate. This year, they became the West African franchise of the Islamic State group.

As their attacks spread across borders, a multinational army from Nigeria and neighbouring countries mobilized and this year drove Boko Haram out of towns. Suicide bomb and attacks on villages continue.