The attack followed two months of calm in the area and took place as Muslims marked Eid al-Adha, the Feast of Sacrifice.
"We found a dreadful scene, around 15 people had been executed, four of whom were from Nigeria," Hassan Ardo, an official from the Diffa governorate told the Tele Sahel television station.
The attackers had also torched 22 houses, a car and a mill, he said, and left four others wounded.
The station said the attack took place Thursday night and was carried out by around a dozen armed militants who had arrived on foot at the village on the banks of the Komadougou Yobe river on the border with Nigeria.
One of the victims was the village chief, the Afani private radio station reported.
In June, 38 civilians were killed -- including 10 children -- in a Boko Haram attack targeting two villages close to Diffa on the border with northeast Nigeria, where the terrorist group has waged a bloody uprising since 2009, leaving at least 15,000 dead and more than two million others homeless.
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