Gunmen attacked villages in troubled north-central Nigeria, killing 29 people and razing houses, survivors and authorities said Tuesday.

Many villagers remained unaccounted for Tuesday evening after the attack in Plateau state, residents said. It was the latest incident in a spiral of violence mainly targeting remote communities in the West African nation.

The gunmen targeted three villages in Plateau state’s Mangu local government area late Monday night and killed several people either with gunfire or after setting their houses ablaze, resident Philip Pamshak said.

“As I am talking to you, they are still attacking people. The tension is still high and there are places the bandits still control, so people are not able to go and check if there are others killed,” Pamshak said.

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Plateau Gov. Simon Lalong said he was disturbed by the attack and directed security forces to search for the suspects and prosecute them, according to a statement issued by his spokesman.

“He (the governor) describes this as yet another attempt by crises merchants and criminals to return the state to the dark days of pain and agony,” said Makut Macham, Lalong’s spokesman.

Such attacks have become rampant in many parts of Nigeria’s northern region, where several armed groups target villages with inadequate security, either killing or abducting residents and travelers for ransom.

Arrests are rare in such attacks, for which no group typically takes responsibility. However, authorities have in the past identified many of the attackers as former pastoralists who took up arms after decades of conflict with farmers over limited access to land and water.

The security crisis has led to thousands of deaths and defied several government and security measures in the last year.

After the latest killings in Plateau, Lalong directed the emergency response agency to visit the affected communities “to bring succor” to victims and their families, many of whom have either fled the area or have lost their homes, adding to Nigeria’s worsening humanitarian crisis.