The death toll from co-ordinated raids on three villages in Niger by suspected jihadists on Sunday has risen to 137.
“By systematically targeting civilians, these armed bandits are reaching a new level of horror and savagery,” the government said.
Earlier a security source blamed militants linked to the Islamic State (IS) group for the attacks in Tahoua region near Niger’s border with Mali.
It is the deadliest massacre in Niger by suspected militants.
The West African nation is facing an upsurge in suspected jihadist violence, with an estimated 300 people dying this year in attacks.
Last week, at least 58 people returning from market were killed in Tillabéri region, also in the south-west near the Mali border, when gunmen targeted their bus.
Militants linked to IS and al-Qaeda are active in the Sahel region – a semi-arid stretch of land just south of the Sahara Desert which includes Mali, Chad, Niger, Burkina Faso and Mauritania.
The Boko Haram group is also active on Niger’s south-eastern border with Nigeria.
In Sunday’s attack in the Tahoua region it was initially thought that 60 people had been killed.
The gunmen, travelling on motorbikes, targeted the villages of Intazayene, Bakorat and Wistane.
They were “shooting at everything which moved”, the AFP news agency quotes a local official as saying.
Adam Sandor, a Canadian academic who researches insecurity in the Sahel, told the BBC that most of those believed to be behind Sunday’s raids were members of the Islamic State in the Greater Sahara (ISGS) group, which is active in Mali and Niger.