Officials said soldiers and the attackers were involved in a shootout near the Giwa barracks in the Maidugur, a haven for the terrorist group Boko Haram, Voice of America reported.
There were no immediate claims of responsibility or reports on casualties.
The gunfight was near the barracks, the army's main installation in the area, Nigeria's Premium Times reported. Witnesses said some of the attackers were dressed in military uniforms
A military jet dropped bombs on the targeted area, officials said.
Witnesses told Premium Times armed police have taken control of some of the major roads leading to government facilities.
The Boko Haram insurgents attempted to enter the barracks but were turned back by soldiers, witnesses said.
Boko Haram, an Islamic militant group, has been fighting to impose Sharia [Islamic] law in Nigeria, which has large Muslim and Christian populations.