Nigerian President Goodluck Jonathan said on Sunday that violence blamed on Islamist group Boko Haram was worse than the 1960s civil war, with sect sympathisers in government and security agencies.

"The situation we have in our hands is even worse than the civil war that we fought," Jonathan said at a church service held to mark armed forces remembrance day.

"During the civil war, we knew and we could even predict where the enemy was coming from ... But the challenge we have today is more complicated."

Jonathan said Boko Haram members and sympathisers could be found throughout society, "some of them are in the executive arm of government, some of them are in the parliamentary/legislative arm of government, while some of them are even in the judiciary.

"Some are also in the armed forces, the police and other security agencies."

Attacks on Christians blamed on Boko Haram have killed more than 80 people since Christmas, sparking fears of a wider religious conflict in a country whose 160 million population is roughly divided between a mainly Muslim north and predominantly Christian south.