Niger's government says Boko Haram fighters have killed at least 38 people in southeast of the country, with most of the victims women and children.
"Members of the Boko Haram terrorist group have attacked the villages of Lamana and Ngoumao... The initial death toll is 38 civilians, among them 14 men, 14 women and 10 children," Interior Minister Hassoumi Massaoudou told public radio on Thursday.
The villages attacked by the fighters are located in the Gueskerou area of Diffa province near Nigeria, parts of whose northeast are under Boko Haram control.
The latest attack is the deadliest in Niger by the armed group since a raid in April on an island in the West African country's side of Lake Chad killed 74 people, 46 of them soldiers.
Massaoudou said three people had been wounded, and admitted to hospital in Diffa's provincial capital. He said Boko Haram had also set fire to more than 100 homes in its latest raid.
Capture and neutralise
A Lamana resident cited by Anfani television said the attackers arrived shortly after 8:00pm (1900 GMT), and that they were "shooting and burning everything in their path".
"Some civilians were burned by Boko Haram members, others were shot dead using firearms," the broadcaster added.
An independent journalist in Diffa told AFP news agency that the Boko Haram fighters crossed over into the region from Nigeria, after they were taken in vehicles to the border.
Niger's security forces were seeking to "capture and neutralise" the attackers, Massaoudou said.
"Air and ground operations are currently underway," he added, saying the government was "doing all it can" to stop Boko Haram from carrying out more attacks.
A double suicide attack blamed on the group caused carnage in Chad's capital N'Djamena on Monday, killing 33 people and wounding more than 100 others.
The armies of Nigeria, Chad, Niger and Cameroon have been fighting a joint campaign against Boko Haram for several months.
Boko Haram wants to create a caliphate in the north-east Nigeria, and thousands of people have been killed since 2009 when the group launched an armed rebellion against the state.