More than 100 people were killed and around 200 wounded after a Nigerian Air Force fighter jet mistakenly bombed a refugee camp during an operation against extremist group Boko Haram on Tuesday, AP reported. Military commander Major General Lucky Irabor acknowledged the incident that occurred in the town of Rann while President Muhammadu Buhari expressed his sadness over “this regrettable operational mistake” and said that assistance would be offered to the state.

The government, however, has not released an official toll of the victims yet. Nigerian military spokesperson General Rabe Abubakar said the incident was never intended. “However, in a military operation such as this, from time to time these things do occur,” BBC quoted him as saying.

Doctors without borders said at least 52 people were killed in the attack in Rann, which is along the border with Cameroon. The International Red Cross in Africa said that six of its workers were killed in the incident. “The safety of civilians must be respected. We are urgently calling on all parties to ensure the facilitation of medical evacuations by air or road for survivors who are in need of emergency care,” Doctors without Borders director of operations Dr Jean-Clément Cabrol said.

In the past, villagers had accused the country’s armed forces of killing civilians during military operations.

Founded in 2002, Boko Haram has launched several operations killing scores of people as part of its mission to make Nigeria an Islamic state. More than 20,000 people have been killed during the group’s attacks, while around 26 lakh people have been displaced. The United Nations has described the situation as the worst crisis in the continent and warned that 51 lakh people risk starvation, AP reported.