AFP/Baghdad

The government of Iraq's autonomous Kurdish region on Sunday released footage it said was of the brazen commando operation it carried out with elite US troops at a jihadist-run prison.

Elite Kurdish forces supported by US Delta Force fighters freed about 70 people who were being held by the Islamic State group near the Iraqi city of Hawijah during a raid on Thursday.

The rare operation, which bore similarities with a raid against a top IS financier in Syria in May, resulted in the first death of a US serviceman since 2011.

It also raised questions over Washington's commitment to its declared "no boots on the ground" policy although the Pentagon stressed that the forces involved in the raid were there in an advisory capacity. 

The footage, apparently shot from a helmet camera, gives little indication as to the identity of the men who were freed from the IS prison north of Hawijah.

With the near constant crackle of gunfire in the background, the video shows what appear to be Delta Force troops and counter-terrorism forces from the Kurdish Regional Security Council (KRSC) -- which released the video -- conducting the raid.

All the footage is shot inside a building and shows a highly-organised, fast-paced operation during which detainees are lined up, searched and extracted.

According to the KRSC, the operation was carried out by 48 Kurdish and 27 US forces and resulted in the release of "69 hostages" and killing of more than 20 IS members.

The Pentagon has said the 69 released were IS members who had been jailed on suspicion of spying or simple local residents, possibly accused of violating the jihadist group's strict rules.

It also said that clear information that the detainees would be executed the same day and visual evidence that their graves had already been dug clinched the decision to launch the raid.

However commentators have questioned why the United States would take such huge risks to take part in an operation, which the KRSC itself admitted did not result in freeing any Kurds.