A government official says suspected armed robbers terrorizing northwest Nigeria raided three villages there, killing at least seven people and wounding seven more.

Zamfara state Information Commissioner Ibrahim Birnin Magaji said Sunday that the attacks focused on the villages of Akuzo, Makera and Usu in the rural region. Magaji said the gunmen attacked the villages Saturday morning as people left the mosque following morning prayers.

The assault appeared to be the work of a violent gang blamed for several mass casualty attacks in the region in recent months as they raid rural villages in Zamfara and neighboring Kaduna state.

In June, gunmen killed at least 27 people in Zamfara state in attacks on villages preparing for a local market day. Another 20 were killed in an October attack.