Last week in northern Nigeria, two drone strikes killed at least 85 people who had been out celebrating a Muslim holiday in a village. In June, dozens of herders and their cattle were hit from the sky, in the state next to the country’s capital. And in 2017, around 100 people were killed in an airstrike on a refugee camp in the country’s northeast.

As the Nigerian military wages a domestic war against extremist militants and armed gangs, its widespread use of airstrikes on its own soil has come with a cascade of more than a dozen accidents that have killed hundreds of civilians in the past six years, according to security analysts.

The repeated errors raise pressing questions for the United States, which trains and equips the Nigerian military and considers Nigeria a key ally in a region of Africa marred by widespread insecurity and coups.

The Dec. 3 attack on a village where hundreds of worshipers were gathered at night for a festive Muslim holiday underscored the deficiencies of West Africa’s largest military. Analysts say the problems include mismanagement, faulty intelligence gathering and a lack of coordination among the different branches of the country’s security apparatus.

Nigeria, Africa’s most populous nation, has for years faced multiple security threats at once, from Boko Haram insurgents in the northeast to armed gangs locally known as bandits across the whole north who pilfer, kill or kidnap civilians for ransom. The northern state of Kaduna, where the attack on the village occurred, has been a prime target of those gangs.

“The fundamental problem that U.S. and Nigerian leaders refuse to acknowledge is that combat air power — drones, warplanes — is not a policing tool,” said Matthew Page, a former State Department expert on Nigeria, and now an associate fellow at Chatham House, a British research group.

“Western democracies don’t use aerial bombings as a policing tool at home, and this is why: because they cause a disproportionate amount of damage,” he said.

The Nigerian military did not respond to questions about systemic problems. But Christopher Gwabin Musa, the Nigerian chief of defense staff, did speak to the bombarding of the celebration last week. He called it a “sad and unfortunate incident” that happened because the military had been tipped off and observed movement consistent with a terrorist attack.

Even as many in Nigeria have grown used to these accidental killings, analysts say, the attack on Tudun Biri, a village in Kaduna, was one too many.

Protesters stormed the National Assembly last week. President Bola Ahmed Tinubu of Nigeria called for “a thorough and full-fledged investigation” into an attack he described as “unacceptable.” The army quickly admitted responsibility, saying it had mistaken the crowds of civilians for a gathering of terrorists.

“They were Nigerians of profound faith and in the moment of the tragedy, they were reciting the Shahada,” Mr. Tinubu said, referring to the Islamic declaration of faith, at a military conference on Monday. “May their souls rest in eternal peace.”

But two residents said in interviews that the police and local authorities had been aware of the gathering for the religious celebration. And the residents said that there was a second strike shortly after the first one, just as they were rushing to rescue the victims, a claim echoed in testimonies collected by human rights organizations.

Hundreds of worshipers had gathered on Tudun Biri’s central square that Sunday, setting up canopies and loudspeakers and installing mats and chairs for the Mawlid religious holiday. Many had not been able to find accommodations, and had planned to spend the night on the square.

Ahmadu Musa, a 37-year-old farmer, said he had left the celebration early to rest from a stomach infection when he heard a jet hover over his village, followed by a loud bang that felt like an earthquake.

At the sight of billowing smoke and a thick fire, Mr. Musa rushed to the square, where one of his two wives, five children and many relatives were attending the celebration, he said. He found his wife and children dead, while other members of his family were only identifiable by their clothing, their bodies unrecognizable.

At least 85 people were killed, according to Nigeria’s main emergency agency, and dozens of others injured. The attack was the deadliest since 2017, when about 100 people were killed in the bombing of a camp with 40,000 refugees, run by Doctors Without Borders.

Nigeria’s security forces have bought attack drones from China and Turkey, according to security analysts, and increasingly resorted to airstrikes to target Boko Haram insurgents and criminal gangs.

Before the strike this month, more than 300 people had been killed in airstrikes carried out by the Nigerian military since 2017, according to a tally by SBM Intelligence, a Nigerian risk consultancy.

It has faced close to no accountability, analysts say.

“The military is given a lot of latitude given how Nigeria is infested with terrorists,” said Confidence MacHarry, a security analyst with SBM Intelligence. “The lack of accountability fuels the culture of impunity.”

An American official, who spoke on condition of anonymity to discuss intelligence assessments, said an initial U.S. assessment concluded that the Nigerian army drone used in the strike was Turkish made. But Pentagon officials said they had no information about the incident and referred questions to the Nigerian military.

Two independent Nigerian analysis firms said the drone used was most likely a Turkish-made Bayraktar TB2, an attack drone popular in Ukraine and among various African militaries such as Burkina Faso, Mali and Niger, among others.

Nigerian soldiers have trained alongside African troops in Pentagon-sponsored exercises. And last year, the Biden administration approved a nearly $1 billion attack helicopter deal with Nigeria.

But for more than a decade, U.S. officials have also periodically raised serious concerns about suspected human rights abuses by Nigerian forces. A State Department inspector general report in 2013, for instance, found that of 1,377 Nigerian soldiers vetted the year before to receive American training, 211 were rejected or suspended because of human rights concerns.

American officials said they were heartened by Mr. Tinubu’s call last week for an investigation into the strikes. But some former U.S. diplomats and senior military officials expressed doubts that any senior official would be held accountable, given the Nigerian military’s lack of transparency, or that improved training would result.

Earlier this year, two members of Congress urged the Biden administration to cancel the helicopter deal with Nigeria, citing human rights abuses that included forced abortions and indiscriminate killings.

J. Peter Pham, a former special U.S. envoy to the Sahel region, which includes countries south of the Sahara, said the incident in Tudun Biri underscored the difficulty with arms purchases from sellers like China and Turkey. The purchases, Mr. Pham said, “might be more easily available or cheaper, but rarely come with the intensive training that Western, especially U.S., packages entail.”

But Mr. Page, the former State Department analyst, argued that even as part of the nearly $1 billion helicopter deal, Nigeria had received far less training than initially advertised by U.S. policymakers and diplomats.

During a visit to Tudun Biri last week, Vice President Kashim Shettima of Nigeria promised to build houses, schools and clinics. Some senators vowed to donate their December salaries to the community. But few expect long-lasting changes, said Mr. MacHarry, the security analyst.

In Tudun Biri, Mr. Musa buried his wife and five children at the local graveyard a day after the strike. Victims who could not be identified were buried in a mass grave.

“We are picking up the remaining pieces of our lives,” Mr. Musa said, adding that several families had left the village for fear of another attack.

Pius Adeleye contributed reporting from Ilorin, Nigeria.