A group of gunmen who disguised themselves as traditional hunters have surrounded a Mali village and killed at least 134 Fulani herders.
It was the deadliest such attack of recent times in a region reeling from worsening ethnic and jihadist violence.
The Fulani ethnic group are semi-nomadic, primarily Muslim and live in various West African nations.
Moulaye Guindo, mayor of the nearby town of Bankass, said armed men, dressed as traditional Donzo hunters, encircled and attacked Ogossagou.
He said another nearby Fulani village, Welingara, had also been attacked, causing "a number" of deaths, but he did not yet know how many.
Security sources said the dead included pregnant women, children and elderly people, and members of the greater Peuhl community who were in contact with survivors said that the village chief and his grandchildren were among the victims.
Graphic video provided to The Associated Press hours after the attack shows bodies sprawled out on the earth next to huts still burning.
The armed attacks took place as a United Nations Security Council mission visited Mali seeking solutions to violence that killed hundreds of civilians last year and is spreading across West Africa's Sahel region.
Francois Delattre, the president of the council who spoke in Mali's capital on Saturday, condemned the massacre as an "unspeakable attack".
One Ogossagou resident, who asked not to be identified, said the attack appeared to be in retaliation, after an Al Qaeda affiliate claimed responsibility for a raid last week that killed 23 soldiers.
That group said that raid was payback for violence by Mali's army and militiamen against the Fulani.
Jihadist groups linked to Al Qaeda and Islamic State have exploited ethnic rivalries in Mali and neighbouring Burkina Faso and Niger in recent years to boost recruitment and render vast swathes of territory virtually ungovernable.