At least 85 civilians were "mistakenly" killed in a drone strike during a Muslim religious celebration in Nigeria on Sunday.
Kaduna state governor Uba Sani said they were killed mistakenly by a military drone strike "targeting terrorists and bandits".
Dozens were also wounded.
Nigeria's president Bola Tinubu on Tuesday called for a thorough investigation into the attack.
The Kaduna State Emergency Management Agency said on Tuesday at least 85 people had died during the attack, giving the first official confirmation of the toll.
"The Northwest Zonal Office has received details from the local authorities that 85 dead bodies have so far been buried while search is still ongoing," the agency said.
Mr Tinubu, who is attending the Cop28 Climate Summit in Dubai, said the "bombing mishap" in a village at Tundun Biri, was "very unfortunate, disturbing, and painful", his spokesman Ajuri Ngelale said in a statement.
"The President directs a thorough and full-fledged investigation into the incident and calls for calm while the authorities look diligently into the mishap," said Mr Ngelale.
One man, who witnessed what happened, told the BBC that there were two attacks.
"The aircraft dropped a bomb at the venue, it destroyed and killed our people including women and children," he said.
"The second bomb was dropped on some of us who went to bring dead bodies of the victims of the first blast. We lost about 34 people in my family and we have 66 injured people in the hospital."
The Nigerian Army is yet to comment on the incident but the Air Force has denied being involved in the mission that led to Sunday's attack.
Nigeria's military, which is backed by the United States, Britain and other non-Western allies in a long war against Islamist insurgents in the northeast, has also been unleashing deadly aerial assaults for years in other parts of the country.
Kaduna is around 100 miles from the capital Abuja.
