- Exchange of gunfire follows the bombing in Maiduguri, Nigeria
- Suspicion fell on the militant Islamic Boko Haram sect
- The group has been responsible for violent attacks in the area
A powerful bomb exploded Tuesday at a military post in the restive, northeastern Nigerian city of Maiduguri, followed by a hail of gunfire, witnesses said.
The witnesses said they saw bodies, but CNN could not confirm any deaths or injuries.
They said the military exchanged fire with the attackers and cordoned off the area.
Suspicion fell on the militant Islamic sect Boko Haram, especially with the Christmas holidays around the corner.
In November, dozens of Boko Haram assailants descended on Damaturu, capital of the Nigerian state of Yobe, and killed more than 100 people in a coordinated series of bombings and gun attacks.
Many of those targeted were Christians, but police stations and mosques deemed "insufficiently Islamic" were also attacked.
Boko Haram translates from the local Hausa as "Western education is outlawed." The group has morphed into an insurgency responsible for dozens of attacks in Nigeria in the last two years.
Boko Haram's targets include police outposts and churches as well as places associated with "Western influence."
In Maiduguri, the epicenter of the insurgency, there is a heavy military presence, with security checkpoints, sandbagged military positions and the scars left by bomb attacks.
Many Christians in northeastern Nigeria have fled their homes as the violence has worsened this year.