An airstrike by the US-led coalition aimed at Islamic State (IS) militants in Iraq may have inadvertently killed up to 10 Iraqi soldiers, the US military has said.

The "friendly fire" incident happened as Iraqi troops were fighting the extremists just outside the IS stronghold of Fallujah on Friday.

The US military said the strikes were in response to requests and information provided by Iraqi security forces on the ground near Fallujah, adding that all coalition strikes were conducted with the approval of the Iraqi government.

The Iraqi Defence Ministry said it had requested aerial support from the coalition, which earlier carried out two successful airstrikes - killing many IS militants.

In a statement, the US military said: "Despite coordination with the Iraqi security forces on the ground, initial reports indicate the possibility one of the strikes resulted in the death of Iraqi soldiers.

"The coalition offers condolences on the unfortunate loss of life of brave Iraq security forces on the front lines in the fight against Daesh (IS).

"To the best of our knowledge, there have been no previous incidents of friendly fire in Iraq involving the coalition during the course of Operation Inherent Resolve."

It said an investigation would be launched into the incident.

Fallujah, 30 miles (50km) west of the capital Baghdad, is IS's main stronghold in Anbar province.

Iraqi forces backed by daily coalition airstrikes have been battling jihadist fighters in the province's capital Ramadi.