Twenty people, many of them women and children, were trampled to death on Monday in a stampede for food and money for refugees in southeast Niger, sources said.
"We have a provisional toll of 20 dead," a medical source said. Aid workers confirmed the account and said about 10 people had been injured.
The accident occurred at a culture centre in Diffa, the main town of a region of that name that abuts Nigeria and Chad.
The region has been repeatedly hit by attacks by Nigeria's Boko Haram jihadist group since 2015.
It hosts 119 000 Nigerian refugees, 109 000 internally-displaced people, and 30 000 Nigeriens who have come home from Nigeria because of the instability in its northeast, according to UN figures released October.
The aid being distributed had been given by Babagana Umara Zulum, the governor of Borno state in northeast Nigeria, a Nigerian official told AFP.
He had come to the region to visit the camps for refugees and the displaced, and had already left the town when the stampede occurred.
"They were distributing food and money - 5 000 naira ($13.75) per person," a local resident told AFP. The naira is Nigeria's national currency.
"Thousands of people, most of them refugees, heard about the handout and left the camps, sometimes travelling up to 100km to get to Diffa," the source said.
Another resident said: "Even ordinary inhabitants of Diffa rushed there in the hope of getting the handout."
"Many women trampled their child to death" in the rush, a medical source said.