At least 20 people were killed on Wednesday in an attack by armed bandits in Nigeria’s northern Katsina state, despite a peace agreement previously reached with the groups, local authorities said.

Faskari district head Surajo Aliyu Daudawa told a local newspaper that bandits carried out the attack in the Duma area of Faskari in Katsina state.

Daudawa said preliminary estimates indicated at least 20 people were killed and many others wounded, with several houses and vehicles set ablaze during the assault.

Nigeria’s northwest has for years been plagued by attacks by armed gangs blamed for killings, kidnappings and looting, despite repeated efforts by authorities to curb the violence through peace deals.