Nigeria's military said it killed scores of armed gang members in a joint air and ground operation in a forested region in the northwest, an area plagued by mass abductions and attacks on villages.

The armed forces said they moved in on Sunday after more than 400 gang members, known locally as bandits, were seen preparing to attack a village in the Bukuyum local government area of Zamfara state.

An air strike killed "several notorious kingpins and scores of their foot soldiers," air force spokesperson Air Commodore Ehimen Ejodame said.

Ground troops intercepted and killed others trying to flee the area in Makakkari Forest, he added.

The armed groups often hold captives for months and demand ransoms for their release.

The government has launched repeated military offensives against them in recent years, but the violence has persisted.