Nigeria's intelligence agency says the Islamic extremist group Boko Haram infiltrated the capital's main airport and was using a teenager to carrying out surveillance.

Tony Opuiyo, spokesman for the Department of State Services, said late Friday a 14-year-old boy was arrested at the international airport in Abuja earlier in the week. The teenager said he spied on the movement of passengers and security and reported back to his handlers, said Opuiyo.

The intelligence agency said it's working closely with the Aviation Security Department and other groups to prevent any possible attacks at Nigeria's airports.

More than 1,000 people have been killed by Boko Haram violence since President Muhammadu Buhari was elected in March with a pledge to wipe out the extremists, whose six-year-old uprising has killed an estimated 20,000 people.