An emergency official in northeast Nigeria said Friday nine people were killed and 23 others injured in an air strike this week that reportedly hit civilians, in the first official tally of victims.

The Nigerian air force confirmed that earlier in the week it sent an aircraft to the area where Boko Haram and Islamic-state affiliates operate, and that it was investigating claims "civilians were erroneously killed".

Since 2009, Nigeria has been fighting a jihadist insurgency in the northeast that has killed more than 40,000 people and displaced nearly two million from their homes.

On Wednesday, a fighter jet opened fire on Buhari village in Yobe state near the border with Niger, which residents said killed 10 people and injured at least 19.

On Friday, the head of Yobe state's emergency management agency Mohammed Goje however said that "nine people died."

"At least 23 people were injured," he added, after visiting the village on Thursday. "They included men, women and children." 

Two of the injured with critical injuries were transferred to a bigger hospital in the state capital Damaturu, he said. 

He said the emergency services have begun repairs of the only solar-powered water borehole in the village destroyed in the air strike.

According to several residents, three fighter jets flew over the village and one of them opened fire.

The Nigerian air force did not confirm or deny the death toll.

"Reports reaching (the) Nigerian Air Force Headquarters alleged that some civilians were erroneously killed while others were injured," spokesman Edward Gabkwet said Thursday.

According to initial information, he said, the aircraft was "not carrying bombs".

But "a board of inquiry has been set up to thoroughly investigate the circumstances of the incident," Gabkwet added.

The governor of Yobe state, Mai Mala Buni, said lives were lost during an air strike on Buhari village, but did not confirm a death toll.

"It could have been an accident or mistaken target, but government will join hands with the security agencies to unravel the root cause of the incident," his spokesman Mamman Mohammed said in a statement.

There have been at least two previous incidents in which Nigerian civilians were killed in military airstrikes.