Scores of Islamist gunmen have attacked a police station, a court and a bank in northern Nigeria, killing seven officers and a civilian, a police chief says.

Wednesday's raid in the town of Gwaram in Jigawa state began at 1am local time and sparked a shootout with the security forces, said Tamari Yabo, the assistant inspector-general of police in charge of the region.

Boko Haram Islamists, waging a brutal insurgency which has killed thousands since 2009, have carried out dozens of attacks in surrounding areas, but Jigawa itself has been spared much of the violence.

"We lost seven policeman. One civilian was also killed," Yabo said of the fighting roughly 100km from Jigawa's capital Dutse.

He told AFP the insurgents came on motorcycles and stolen vehicles, specifically targeting the town's main police station as well as a bank and a court that enforces Islamic law, or sharia.

"The attack resulted in an hours-long shootout with our men but they were out-gunned and out-numbered by the terrorists," Yabo said. Security personnel typically use the word "terrorist" when discussing Boko Haram.

Jigawa shares a border with Yobe, a Boko Haram stronghold and one of three northeastern states that has been under emergency rule since May of last year.

The military is launching a major offensive in the region to crush Boko Haram's uprising, which the insurgents say is aimed at creating a strict Islamic state in northern Nigeria.

Violence in the region has already killed some 1500 people this year.

Senior military officials have insisted that Boko Haram fighters have been flushed out of their traditional strongholds in parts of Yobe and Borno state.

It is possible that some Islamists have fled to Jigawa to evade military pressure as the state is not covered by the emergency rule and therefore has a relatively light deployment of security personnel.