All the dead were male and from the villages of Doukou Saraou and Doukou Makani, which lie barely a kilometre (half a mile) apart, the official said.
A security source confirmed the attacks but did not give a death toll.
The unstable and arid Tillaberi region lies in the tri-border zone where southwestern Niger meets Mali and Burkina Faso — a hotbed of activity for insurgents linked to Al-Qaeda and the Islamic State group.
Despite a state of emergency and deployment of large numbers of anti-jihadist forces, attacks are common.
French soldiers are fighting alongside Nigerien counterparts in Tillaberi, the authorities in both countries say.
The United Nations said last week that nearly 11,000 people in southwestern Niger had fled their homes this month.
The Tillaberi region has 150,000 internally displaced people, according to the UN.
Several villages in Anzourou district were hit between May 2020 and August 2021 when dozens of people were massacred by gunmen on motorbikes.
One of the poorest countries in the world, Niger is also fighting long-running jihadist violence in its southeast, which spills across the border from Nigeria.