Air raid kills Iraqi pro-government tribal fighters

An air raid killed 21 Iraqi pro-government Sunni tribal fighters early on Wednesday in an area south of the Islamic State group's stronghold in Iraq.

It was unclear whether it was the Iraqi military or the US-led coalition against IS which mistakenly hit the fighters. Both air forces are operating in the area.

The raid happened at around 1am on Wednesday east of the town of Qayyarah, which was recaptured from IS in August, the officials said.

Sheikh Nazhan Sakhr al-Lihaybi, the commander of the fighters who were killed, said they had succeeded in repelling an attack by IS militants in the area, and were bombed when they gathered after the end of the fighting.

Agriculture minister Falah Hassan Zaidan, whose tribe resides in the Qayyarah area, also said that 21 tribal fighters were killed and confirmed the timing of the strike.

Lihaybi said that the air raid also wounded five fighters, while Zaidan put the number at four.

The US-led coalition has been carrying out strikes against IS in Iraq since 2014, and the country's military also targets the militants with warplanes and helicopters.

The deadly strike comes as Iraqi forces prepare for a final push to retake Mosul, the last IS-held city in the country.

The Mosul operation - which Western officials have indicated could start this month - will involve a heterogenous coalition of sometimes rival Iraqi forces including soldiers, police, Kurdish peshmerga fighters, and both Sunni and Shia militias.

After it is launched, these forces will have to fight their way through IS-held territory - sometimes over distances of dozens of kilometres [miles] - before surrounding the city and then launching an assault to retake it.

The issue of which forces will actually enter the city is a contentious one, and there has been no public announcement of the roles the various forces will play.