WASHINGTON (AFP) - The Pentagon on Friday identified the US serviceman killed during a hostage rescue mission in Iraq as Joshua Wheeler, the first American soldier to die there since 2011.

Wheeler, 39, a master sergeant from Oklahoma, was killed on Thursday during an anti-Islamic State military raid near Hawijah, Iraq.

The Pentagon said Wheeler lost his life during an operation involving US special forces and Kurdish peshmerga fighters that freed some 70 hostages.

The operation was part of a broader US-led campaign that commenced in June of last year, targeting the Islamic State in Iraq and Syria (ISIS) group.

According to unnamed sources cited in other media, he was part of the elite Delta Force, often used for hostage-rescue and counterterrorism operations.

Wheeler, who had been awarded numerous bronze stars and other commendations, had previously served as an Army Ranger, doing three tours in Afghanistan and Iraq.

He was then deployed 11 times as part of special operations forces, the Army said.

The United States has 3,500 troops in Iraq to train, advise and assist Iraqi forces in fighting back the extremist Islamic State group.

Some of those troops supported Kurdish forces Thursday as they stormed an ISIS prison, capturing five ISIS militants and freeing the prisoners, some of whom were Iraqi security forces, according to the Pentagon.

The US soldiers were not intending to go inside the compound or be directly involved the raid, "but the Kurds came under heavy fire," a defence official told AFP.

"They were in need of protection. So the US troops engaged to finish the job," the official said.

The Pentagon said Wheeler is survived by a wife and four sons.