The Nigerian air force said on Thursday it may have killed and injured civilians while pursuing suspected Islamist insurgents in the northeast state of Yobe, in an incident that residents said left at least six people dead.

Nigeria's northeast is the hotbed of two Islamist insurgencies: Boko Haram and Islamic State's West African (ISWAP) branch, which split from the former group in 2016.

An air force spokesman said a fighter jet responded to intelligence on suspicious movements of suspected insurgents from either the Boko Haram group or ISWAP on Wednesday and fired "some probing shots", killing and injuring civilians in the process.

Air Commodore Edward Gabkwet did not specify numbers.

"Unfortunately reports reaching Nigerian Air Force headquarters alleged that some civilians were erroneously killed while others were injured," he said in a statement.

"Therefore a board of inquiry has been set up to thoroughly investigate the circumstances of the incident."

Three residents in Yobe's Yunasari local government area told Reuters that the air force jet had flown over the village on Wednesday morning before there were explosions

"We saw it hovering around the village and suddenly we heard two loud bangs," resident Ibrahim Goni told Reuters by phone.

One resident said he had lost four of his relatives while another said his mother and niece had died in the incident.

At least 45 people had been and were taken to Gaidam General Hospital in Yobe, the three residents said.

Nigeria's war with Boko Haram and ISWAP has spawned one of the world's worst humanitarian crises, with millions of people dependent on aid. 

Reuters