The attacks on the villages of Tchombangou and Zaroumadareye were carried out by "terrorists who came riding about a hundred motorcycles", according to Almou Hassane, mayor of the Tondikiwindi commune that administers both villages.
"There were up to 70 dead in Tchomabangou and 30 dead in Zaroumadareye," he told AFP news agency, adding he had just returned from the scene of the attacks.
Saturday's attack began with fighters arriving in the village of Tchombangou by motorcycle, according to RFI's Niamey correspondent Moussa Kaka. A band of young people then gathered to form a vigilante group and killed the two jihadists with machetes.
Reprisal attacks were quickly mounted by the jihadists, with more fighters arriving by motorcycle, said Kaka.
The villages are in the district of Mangueize, in the area of Ouallam, which has frequently been the target of hardline Islamist fighters.
Three years ago in nearby Tongo Tongo, US special forces and Nigerien soldiers were killed by jihadists.
Intercommunal violence resulting from this latest attack has not been ruled out, given the lack of any presence of security forces, although the authorities would be working to stop any further violence sparked by the attacks, according to Interior Minister Alkach Alhada.
Niger has previously seen attacks by Islamists militants targeting the area near the western border with Mali and Burkina Faso, as well as the south-eastern border with Nigeria.
