According the UN, at least one other aid worker remains critically injured and another three are still missing. Eight members of the Nigerian national security forces were also killed.

At the time of the attack, over 40 humanitarian workers were in Rann. All humanitarian personnel have been evacuated from Rann, and all humanitarian deliveries in the area have been temporarily suspended.

“The Secretary-General expresses his deepest condolences to the affected aid workers, their families and to the Government and people of Nigeria,” said a statement from UN Spokesman Stéphane Dujarric, adding that Guterres wishes those injured a swift recovery.

The UN chief recalled that attacks targeting civilians and civilian infrastructure violate international humanitarian law.

“Those responsible for these and other atrocities in Nigeria must be apprehended and prosecuted,” said the statement,” adding that the Secretary-General calls on all the parties to ensure at all times the protection of all civilians in Nigeria.