File photo shows Nigerian soldiers participate in an operation in Nigeria's northeastern state of Borno, March 16, 2016. (Xinhua/Wale Salau)

LAGOS, Sept. 6 (Xinhua) -- The Islamic State (IS) had its spies operating from internally displaced persons (IDPs) camps in the restive state of Borno in northeastern Nigeria, Nigerian police said Wednesday.

It was established that three among the 22 Boko Haram insurgents arrested two months ago were IS members, Ahmed Bello, a deputy police chief, told reporters in Maiduguri, the state capital.

He spoke while giving update on security situation at a humanitarian and development coordination forum in Maiduguri.

The terrorists usually stationed their stooge at the IDP camps to perpetrate chaos, without being noticed, he added, noting that the arrest of the culprits had led to drastic reduction in cases of bomb blasts in Maiduguri metropolis.

In June, local media widely reported that the West African country was under a threat by the IS, but the defense authorities was quick to say the country was not under threat by any local or foreign terrorist groups.

The media report, citing unnamed sources, further suggested that "leaders of ISIS are sneaking battle-hardened jihadists from Syria into Nigeria to train terrorists there for possible attacks in Britain".

In 2016, a faction of Boko Haram had pledged its allegiance to the IS after the government forces had dislodged them from Sambisa Forest, a former enclave of the terror group in Borno.

Boko Haram has been blamed for the death of more than 20,000 people and displacement of 2.3 million others in Nigeria since 2009.