WASHINGTON - The Islamic State group killed a Navy SEAL during an "orchestrated attack" in Iraq on Tuesday, a US defence official said.

The Pentagon had earlier announced a US troop died during an IS attack on a Peshmerga position north of Mosul. "It was an orchestrated attack with shots and multiple IEDs (bombs) going off," the official told AFP. Another defence official had earlier said the serviceman was killed by "direct fire." Pentagon press secretary Peter Cook said the attack took place about three to 5km behind the forward line of troops, adding that the troop was advising and assisting Peshmerga forces."This sad news is a reminder of the dangers our men and women in uniform face every day in the ongoing fight to destroy ISIL and end the threat the group poses to the US and the rest of the world," Cook said, using an acronym for the IS group.

"Our coalition will honour this sacrifice by dealing ISIL a lasting defeat."

Special operations forces are playing a key role in America's campaign against the IS group in Iraq and Syria, where the commandos are training and advising local forces fighting the militants.