MAIDUGURI, Nigeria—Officials say suspected fighters from a radical Islamist sect beheaded three people in a northeastern Nigerian city where gunfire has echoed through the street.

The violence happened Wednesday in Maiduguri and appeared to be the work of the sect known as Boko Haram.

Lt. Col. Sagir Musa said three people had been beheaded in an early morning attack in a Maiduguri neighborhood. Later, witnesses and officials said four dead bodies were found in another neighborhood. Residents say a Boko Haram fighter also shot and killed another person, drawing mortar fire from the military.

Boko Haram is waging a bloody sectarian fight against Nigeria's weak central government, which has been unable to stop the violence. Authorities blamed the sect for killing five others Tuesday in the northern city of Kano.