ABUJA, Nigeria (AP) — A Nigerian military attack that used drones to target rebels instead killed some civilians, government and military officials said Monday. The misfire during a religious celebration was the latest such errant bombing of local residents in Nigeria’s violence hot spots.

Muslims observing Maulud on Sunday night in Kaduna state’s Igabi council area were “mistakenly killed and many others injured” by the drone “targeting terrorists and bandits,” Gov. Uba Sani said.

Officials did not confirm the number of people killed, but a large crowd typically gathers in the state to celebrate that holiday that commemorates the bird of the Prophet Muhammad.

Amnesty International’s Nigeria office said 120 people were killed in the attack, citing reports of its workers and volunteers in the area. “Many of them were children (and) more dead bodies are being discovered,” Isa Sanusi, the organization’s director in Nigeria, told The Associated Press.

At least 50 bodies were recovered, according to Igabi resident Mustapha Rufai. “They said they mistakenly threw a bomb on them,” he said.

Extremist and rebel attacks have ravaged parts of Nigeria’s northwest and central regions . The country’s forces frequently target the hideouts of armed groups with aerial bombardment but have sometimes bombed villagers.

The latest incident caused outrage among citizens, reminding many of the rampant allegations of human rights abuses by Nigerian security forces that have raised concerns from Western allies such as the United States.

The head of the Nigerian army division in charge of operations in Kaduna was quoted by the state government as saying during a security meeting on Monday that the drone operation was a routine one.

“The Nigerian army was on a routine mission against terrorists but inadvertently affected members of the community,” a statement issued by the Kaduna State Ministry of Internal Security quoted Major Valentine Okoro, head of the army division, as saying.

“Search-and-rescue efforts are still ongoing, as dozens of injured victims have been evacuated” to a hospital for treatment, Kaduna Security Commissioner Samuel Aruwan said.

The Nigerian air force issued a statement saying it did not carry out any operation in Kaduna but that it was “not the only organization operating combat armed drones” in the region. A Nigerian army spokesperson did not immediately respond to an Associated Press inquiry.

Local media reported that villagers fled the area, fearing more drone attacks. Activists have said that similar incidents were not investigated in the past, leaving victims and survivors without adequate compensation or justice.

Sani, the state governor, said government officials were sent to the village affected Sunday and to meet with the families of victims. An investigation was underway, he said.

“We are determined to prevent a repeat of this tragedy and reassure our people that their protection would be prioritized in the sustained fight against terrorists, bandits and other criminal elements,” he said.