The current activities of Boko Haram terrorists have given rise to the assumption that 60 percent of them are not Nigerians, Chief of Army Staff Tukur Buratai said Wednesday.

The comments on the extremist group were made when the lieutenant general was in Maiduguri, the capital city of Borno State, for receiving the Special Representative of the U.N. Secretary-General, Mohammed Ibn Chambas, at the headquarters of the Theatre Command of Operation Lafiya Dole at the Maimalari Cantonment.

“Your Excellency, I want to bring to your attention that while the Boko Haram (insurgency) can be said to have started in Nigeria, by and large as at today, I can say that almost 60 percent of the insurgents are from our neighboring countries. You can see that almost all of the recently surrendered insurgents are not Nigerians," Buratai reportedly said.

“This is a challenge that impacts more on the Nigerian side than the other countries. But by and large, our military is up to the task and we will continue to do our best to ensure that our country is secured."

Meanwhile, over 1,000 Chadians who are believed to have been fighting for Boko Haram have returned home.

Buratai also said that there was no doubt that the terrorists had been defeated but Nigerian troops would continue with their operations until the insurgents finally surrender.

Boko Haram, which pledged allegiance to the Islamic State group in 2015, has been active in Nigeria since 2009, and in 2015 upped its activities across Nigeria’s borders in Cameroon, Chad and Niger.

Earlier, Chambas said that his visit was an expression of the U.N.’s solidarity with Nigeria in the fight against Boko Haram and efforts to restore peace to the country's northeastern region. He noted that the immediate consequence of the insurgency was the "huge humanitarian crisis" in the northeast and assured that the U.N. had stepped up efforts to address it.