Kurdish authorities said their troops conducted a joint raid with US forces Thursday, killing a militant financier near a western Iraqi town that is far from where they usually operate.

"A joint operation was conducted by our Directorate General of Counter Terrorism and US Special Forces in the vicinity of Al-Qaim near the Iraqi-Syrian border," the Kurdish Regional Security Council said in a statement.

It said the raid killed Sami Jassem Mohammed al-Juburi, a man sanctioned by the US Treasury Department for supervising operations to fund the Islamic State group, including via the sale of oil and gas.

The statement did not specify the exact location of the operation.

The US-led anti-IS coalition confirmed its forces had taken part in a joint raid in Iraq on Thursday.

"Coalition forces conducted a combined operation in Iraq, Aug. 11, against an (IS) associated target," the coalition said in a statement emailed to AFP.

"We are assessing the results of the operation," the statement said, adding that "the mission was effectively coordinated with the government of Iraq and conducted in partnership with Iraqi security forces."

Al-Qaim is located more than 200 kilometres (125 miles) from the closest Kurdish lines, and a raid involving Kurdish forces in the area has the potential to anger Iraq's federal government.

Baghdad is at odds with the country's autonomous Kurdish region over long-running disputes about resources and territory.

US special forces also conducted a joint raid with Kurdish troops against IS in Iraq's Kirkuk province last year -- an operation in which an American soldier was killed.

That raid was also politically sensitive, as it involved Kurdish forces affiliated with the ruling Kurdistan Democratic Party operating in Kirkuk, where the Patriotic Union of Kurdistan, a party that has its own troops, holds power.

The US-led coalition is carrying out air strikes targeting IS, which overran large areas of Iraq in 2014, and also providing advise and other assistance to forces battling the militants.

US President Barack Obama repeatedly pledged there would be no "boots on the ground" to combat IS, but has sent American special forces to target the jihadists, who have so far killed three members of the US military.