Gunmen have assaulted a police station in the northern Nigerian city of Kano, where attacks claimed by a radical Islamic sect killed more than 180 people last week.

Witnesses say a group of gunmen converged Tuesday night on the station in Kano's densely populated Sheka area and ordered civilians to move away from the building. They say the attackers then hurled bombs at the station and sprayed it with gunfire, some shouting “God is great.”

The militant group Boko Haram claimed responsibility for coordinated bombings in Kano on Friday that killed at least 185 people. President Goodluck Jonathan has since renewed a vow to stem the violence in the region.

In Kano Wednesday, witnesses say there were no police in sight as a large crowd made up mostly of youths cheered outside the police station and jumped atop burned police vehicles. Inside the blood-splattered building, jail cell doors were wide open.

There were no immediate reports of casualties nor claims of responsibility.

This week, Human Rights Watch said Boko Haram has killed at least 935 people since 2009, using violence and terrorism to try to turn northern Nigeria into a conservative Islamic state.

Mr. Jonathan has declared a state of emergency in parts of the north, where Boko Haram has carried out most of its attacks.

Africa's most populous country is divided between the mostly Muslim north and largely Christian south. The country has endured spates of sectarian violence over the years, though some of the conflict stems from economic and political factors as well.