Washington (AFP) - US Apache helicopters have struck an Islamic State target for the first time in Iraq, the Pentagon said Monday.

The sophisticated attack choppers destroyed an IS car bomb Sunday near Qayyarah, which is about 50 miles (80 kilometers) south of Mosul, the group's main stronghold in Iraq.

"The government of Iraq approved the use of Apaches in support of ISF (Iraqi Security Forces) operations," Defense Department spokesman Christopher Sherwood said.

"The strike was vetted and approved through the same process the (US-led) coalition uses for all strikes."

Pentagon chief Ashton Carter has since early December made it clear to the Iraqi government that the US military is willing to use its Apaches based in Iraq to support local forces.

But the government had until now declined. US officials say this is because Prime Minister Haider al-Abadi didn't want to anger Shiite militias, who oppose the ramping up of US combat operations in Iraq.

Still, coalition warplanes and drones have since August 2014 been bombing IS targets in Iraq and Syria after the jihadist group overran large parts of the two countries.

The Apache strike came as Iraqi forces advanced towards Qayyarah with the eventual aim of retaking Mosul.

Iraqi forces are also battling IS fighters in Fallujah, which lies 30 miles west of Baghdad and is the group's other main Iraqi bastion besides Mosul.