About 20,000 Nigerians have been forced to flee escalating violence in Nigeria's northwest region to the neighbouring Niger Republic since April, a United Nations Refugee Agency spokesman said on Tuesday.
Kaduna, Zamfara, Katsina and Sokoto - all in the northwest - have been experiencing an uptick in killings and kidnappings in recent months.
"People leaving Nigeria, and arriving in Niger's Maradi Region, speak of witnessing extreme violence unleashed against civilians, including machete attacks, kidnappings and sexual violence," UNHCR spokesman Babar Baloch said on Tuesday. "The majority of the new arrivals are women and children."
He said more than 18,000 people have already gone through the initial registration.
Niger currently hosts about 380,000 refugees from Nigeria, Mali as well as its own citizens.
The Nigerian government said "unpatriotic" traditional rulers were culpable in the killings, especially in Zamfara State.
Defence minister Mansur Dan Alli said the chiefs were providing intelligence to bandits and feeding the military false information.
"Some unpatriotic persons including highly placed traditional rulers in the areas were identified as helping the bandits with intelligence to perpetuate their nefarious actions or to compromise military operations," Dan Ali said in April.
The government also fingered mining in Zamfara as one of the reasons for the recent violence and suspended activities of miners in the state.
The failing security in the region was one of the issues governors from the northern region discussed with President Muhammadu Buhari at a meeting in Abuja on Monday.
"I am acutely aware of the situation, but I have learnt more today," Buhari told the governors, according to release by his media assistant Garba Shehu.