At least 20 fishermen were killed accidentally in a Nigerian military strike on a jihadist camp in northeast Nigeria, two security sources and locals told AFP on Monday.

A Nigerian fighter jet early on Sunday bombarded Kwatar Daban Masara in Lake Chad, which straddles Nigeria and neighboring Niger, Chad, and Cameroon, the sources said. The area is a bastion for the IS-affiliated Islamic State West Africa Province (ISWAP).

The reports of casualties came less than two weeks after officials say another air strike on a village killed nine civilians in Nigeria’s northeast where the military is battling a 12-year Islamist insurgency.

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Nigeria Air Strike Kills 20 Fishermen: Sources