A Nigerian Air Force fighter jet on a mission against Boko Haram extremists mistakenly bombed a refugee camp Tuesday, killing dozens of people.
Military commander Maj.-Gen. Lucky Irabor confirmed an accidental bombardment in the northeastern town of Rann, near the border with Cameroon, saying "some" civilians were killed.
A spokesman from Medecins Sans Frontieres (MSF) said at least 52 people were killed and 120 injured in an airstrike on a refugee camp in the country's northeast.
A Borno state government official, who was helping to coordinate the evacuation of wounded from the remote area by helicopters, had earlier said more than 100 refugees and aid workers were among the dead. He spoke on condition of anonymity because he was not authorized to speak to reporters.
It was believed to be the first time Nigeria's military has admitted to making such a mistake in a region where villagers have in the past reported civilian casualties in the near-daily bombings targeting the Islamic militants.
The International Committee for the Red Cross said six staff workers with the Nigerian Red Cross were among the dead and 13 were wounded.
"They were part of a team that had brought in desperately needed food for over 25,000 displaced persons," spokesman Jason Straziuso said in a statement from Nairobi, Kenya.
Two soldiers were also wounded as well as Nigerians working for Doctors Without Borders, Irabor said, without giving a precise figure.
"This large-scale attack on vulnerable people who have already fled from extreme violence is shocking and unacceptable," said Dr. Jean-Clément Cabrol, the aid group's director of operations. "The safety of civilians must be respected."
Irabor said he ordered the mission based on information that Boko Haram insurgents were gathering, along with geographic co-ordinates. It was too early to say if a tactical error was made, he said.
The general, who is the theatre commander for counterinsurgency operations in northeast Nigeria, said the air force would not deliberately target civilians but there will be an investigation.
Some of the nearly 300 Chibok schoolgirls kidnapped by Boko Haram in 2014 and freed last year have said three of their classmates were killed by air force bombardments, according to the freed girls' parents.
Boko Haram's seven-year-old Islamic uprising has killed more than 20,000 people and forced 2.6 million from their homes, creating the continent's worst humanitarian crisis, with the United Nations warning some 5.1 million people face starvation.