At least 85 civilians were killed when an army drone attack erroneously targeted a religious gathering in northwest Nigeria, officials confirmed Tuesday, as the president ordered a probe into the latest in a series of such deadly mistakes in Nigeria's conflict zones.

The strike took place Sunday night in Kaduna state's Tudun Biri village while residents observed the Muslim holiday marking the birthday of the Prophet Muhammad, government officials said. The military believed it was "targeting terrorists and bandits," officials said.

At least 66 people also were injured in the attack, the National Emergency Management Agency said in a statement. Eighty-five bodies, including of children, women and the elderly, have been buried so far, as a search continues for any additional victims, the agency said.

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Nigeria's army chief, Lt. Gen. Taoreed Lagbaja, apologized for the drone strike during a visit to the village Tuesday and said it had been carried out "based on the observation of some tactics usually employed by bandits."

"Unfortunately, the reports we got revealed it was innocent civilians that the drone conducted a strike on," Lagbaja said.

Since 2017, some 400 civilians have been killed by airstrikes that the military said were targeting armed groups in the deadly security crisis in the country's north, according to the Lagos-based SBM Intelligence security firm.

"The incidence of miscalculated airstrikes is assuming a worrisome dimension in the country," said Atiku Abubakar, Nigeria's former vice-president and the main opposition presidential candidate in this year's election.

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Nigerian President Bola Tinubu ordered "a thorough and full-fledged investigation into the incident." However, such investigations and their outcomes are often shrouded in secrecy.

Nigeria's military often conducts air raids as it fights the extremist violence and rebel attacks that have destabilized Nigeria's north for more than a decade, often leaving civilian casualties in its wake, including in January when dozens were killed in Nasarawa state and in December 2022 when dozens also died in Zamfara state.

Maj. Gen. Edward Buba, a spokesman for Nigeria's Defense Headquarters, said in a statement Tuesday that terror suspects often "deliberately embed themselves within civilian population centers," though he wasn't speaking specifically about Sunday's holiday gathering.

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Analysts have in the past raised concerns about the lack of collaboration among Nigerian security agencies as well as the absence of due diligence in some of their special operations in conflict zones.

One major concern has been the proliferation of drones within Nigerian security agencies such that "there is no guiding principle one when these can be used," according to Kabir Adamu, the founder of Beacon Consulting, a security firm based in Nigeria's capital, Abuja.

"The military sees itself as a little bit over and above civilian accountability as it were," Adamu said.

In the incident in Nasarawa in January, when 39 people were killed, the Nigerian air force "provided little information and no justice" over the incident, Human Rights Watch said.

Such incidents are enabled by a lack of punishment for erring officers or agencies, according to Isa Sanusi, Amnesty International's director in Nigeria.

"The Nigerian military is taking lightly the lack of consequences ... and the civilians they are supposed to protect are the ones paying the price of their incompetence and lack of due diligence," Sanusi told The Associated Press.