Medecins Sans Frontieres (MSF) said this the Nigerian air force killed at least 52 people in an air strike on a refugee camp.
The air strike was intended to target Boko Haram fighters, the Nigerian air force said.
"At least 52 people were killed and 120 wounded," Tim Shenk, a spokesperson for MSF told Reuters.
"The organisation's medical and surgical teams in the region are preparing to treat evacuated patients," Mr Shank added.
A spokesperson for the International Committee of the Red Cross said that six of its workers were killed and 13 wounded.
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