Reports from Kaduna state say gunmen attacked the Galadimawa market in Giwa Local Government Area, causing heavy casualties.
A statement issued by the state commissioner of security and internal affairs, Samuel Aruwan, said the gunmen killed two vigilantes and five others.
In the attack, gunmen who went to the market on 15 motorcycles set fire to a car and 330 bags of maize in a trailer owned by a driver named Alhaji Yusuf Tumburku.
The robbers reportedly entered the market at around 4pm and opened fire on protesters.
But later security forces including the air force pursued the thieves where they managed to kill some of them, according to a statement issued by the commissioner.