At least 60 people have been killed in a series of attacks on villages by armed gangs.
Last week, Nigeria's armed forces launched a series of bomb raids on camps in the northwest region in its latest attempt to curtail violence in the area.
In an apparent retaliation attack, armed gang members raided five villages in the Sabon Birni district on Monday, killing 18 people.
Rival communities in the region have been embroiled in years of violent conflict over land, with armed gangs and vigilante groups carrying out reprisal killings and ransom kidnappings.
According to the ICG, northwest Nigeria risks becoming a "land bridge" to jihadist groups across the Sahel region and called for stronger cooperation between Nigeria and Niger to prevent trafficking of arms on the border.