The death toll from Tuesday's attack on a mosque in northwest Nigeria has risen to at least 30, local sources told AFP on Wednesday, after an initial report put the number at 13.

"Bandits," as members of criminal gangs are locally known, attacked a mosque in the town of Unguwar Mantau, in the Malumfashi region of Katsina State, on Tuesday.

"Nine worshippers were killed instantly and many more died during the day. The latest death toll stands at 32," Nura Musa, a resident of the town, told AFP on Wednesday.

The day before, Aminu Ibrahim, a local elected official, had told the Katsina Assembly that 30 people had been killed.

For years, "bandits" have been preying on rural communities in northwest and central Nigeria, looting villages, kidnapping residents for ransom, and burning down homes after ransacking them.

The attack on worshippers praying early in the morning came despite a series of recent peace agreements in Katsina State aimed at stemming the tide of gang attacks, although Malumfashi was not among the local authorities that recently signed truces.

"Incessant attacks"

Nura Musa told AFP that Tuesday's attack followed an ambush by local militiamen on a bandit gang over the weekend.

Local vigilante groups were created to bolster Nigeria's security apparatus, but they often find themselves overwhelmed or provoke reprisals from gangs.

"The militiamen stand guard from dusk to dawn, patrolling the village and its surrounding areas to repel the bandits," he explained.

After completing their shift, they went to the mosque "at dawn to pray with other worshippers," he added.

"While they were praying, the bandits launched a surprise attack on the mosque. They opened fire on the worshippers and fled," he said.

The "bandits" also attacked other nearby villages and kidnapped "several people," Mr. Musa said.

Nigeria's banditry crisis has its roots in conflicts between herders and farmers over land and water, which have spiraled into organized crime.

Gangs have made cattle rustling, kidnapping, and taxing farmers a significant source of income in poor rural areas, where the government has long had little government presence.

Bandits are also known to take advantage of truces reached with communities to establish safe havens in areas covered by these agreements, while continuing to launch attacks elsewhere.

Security in Birnin Gwari district of Kaduna state has improved following a truce in November, but neighboring Katsina and Niger states have seen a surge in attacks.

"The situation has become unbearable. Our people can no longer live in their villages because of these incessant attacks," said local official Aminu Ibrahim.