Violence returned to northern Nigeria on Monday when gunmen believed to members of the Boko Haram Islamist sect attacked a police station in Kano.

A local police chief confirmed the attack but provided no further details.

Another attack took place Monday in Maiduguri, east of Kano, where a market was hit. There were no reported deaths or injuries in either attack.

Kano, the major city in northern Nigeria, was the scene of last month's attack by Boko Haram militants in which at least 185 people died. Authorities there imposed a dusk-to-dawn curfew following that attack.

The past three months have seen a major increase in Boko Haram attacks, targeting mostly police stations. The sect is seeking to establish Sharia law across much of the country.

Nigeria is Africa's most populous nation with its 160 million citizens roughly divided by the largely Muslim north and the mostly Christian south.

President Goodluck Jonathan has declared a state of emergency in parts of the north, the site of most of the violence.