Nigeria soldiers
Nigerian officials say a growing number of Boko Haram members have been trying to infiltrate major cities outside the group's northwest stronghold. Above, soldiers patrol a bridge above the Komadougou Yobe River, which separates Niger from Nigeria in Diffa, Niger, March 25, 2015. REUTERS/Joe Penney

Militants with the Nigerian Islamist extremist group Boko Haram have sought to spread their violent campaign across the country in recent months, an intelligence official said Sunday. Tony Opuiyo, a spokesman for the Department of State Services, said a growing number of Boko Haram agents has been caught trying to infiltrate Lagos, the country’s largest city, as well as other population centers, the Associated Press reported.

The group has attempted to extend its reach in the country as government forces have continued to push militants out of urban areas in their traditional stronghold of northeastern Nigeria, Opuiyo said. Security forces have reportedly arrested 14 suspects throughout the country, including in Lagos and Abuja, the country’s capital, in the last two months. Some of those arrested have included cell leaders, including those involved in recent suicide bombing attacks, the AP reported. A teenager reportedly was arrested Friday spying on the group’s behalf at Abuja’s international airport.

Boko Haram has waged a brutal six-year insurgency in Nigeria’s northeast region in hope of driving out the central government and establishing an Islamic state in its place. The country has seen upward of 15,000 deaths as a result of fighting between the government and Boko Haram and attacks by the extremist group since it turned violent in 2009.

Nigerian President Muhammadu Buhari, elected earlier this year in a heated campaign that focused primarily on security, tasked newly sworn-in military chiefs earlier in August with ending the bloody six-year insurgency in just three months. Under his leadership, Boko Haram has faced considerable setbacks and has been driven out of some 25 towns, but has in response upped retaliatory attacks on population centers. The group is believed to have killed about 1,000 people since Buhari was elected.

Militants released a video in March pledging allegiance to the Islamic State group based in Syria and Iraq and also called ISIS or ISIL. That same month, Boko Haram members released an ISIS-style beheading video of two men accused of spying.