Nigerian troops have killed 25 militants in a battle in Nigeria's northern state of Kano, the authorities said.
Police said the soldiers were still pursuing some of the militants fleeing from their base in Panshekara, a suburb of Kano.
Unidentified gunmen attacked the Panshekara police outpost in Kumbotso council area of Kano Tuesday and killed a police officer, his wife and 11 policemen.
The general elections started in Nigeria Saturday amid violence. About 28,000 candidates from 50 parties are in the fray.