The Nigerian military says an explosion ripped through a church on an army base on Sunday, with reports of an unknown number of casualties.
Reuters cited military sources as saying the blast was from a suicide car bomb that killed at least five people and injured dozens more.
The incident took place inside the Jaji military barracks in Nigeria's northern Kaduna state after a church service.
No one has claimed responsibility, but several churches in the state have been attacked in recent months by the Islamist sect Boko Haram. The insurgent group is fighting to overthrow the government and impose an extreme form of Sharia law.
Jaji is some 30 kilometers from the state capital Kaduna city which has been hit in the past by deadly attacks blamed on Boko Haram.
Boko Haram's insurgency has killed at least 2,800 people since an uprising in 2009, according to Human Rights Watch, and the group has become Nigeria's largest security threat.