Mattis says US working to de-escalate Kirkuk tensions

US Defence Secretary Jim Mattis said on Friday that the United States is working to ensure tensions between Kurdish and Iraqis forces around Kirkuk do not escalate.

Thousands of Iraqi troops and Kurdish fighters are engaged in a tense stand-off in the disputed oil-rich province of Kirkuk.

Baghdad had reportedly set a 2am Sunday deadline for the Kurds to surrender positions in the province taken during the fightback against the Islamic State group over the past three years.

The face-off is taking place on either side of a river cutting through the city.

"We have got to work on this, the secretary of state has the lead, but my forces are integrated among these forces and they are working too, to make certain we keep any potential for conflict off the table," Mattis told reporters, according to Reuters.

Mattis said he was aware of troop movement in the area around Kirkuk but had not heard of any fighting and called on both sides to focus on fighting the Islamic State group.

"We can't turn on each other right now. We don’t want this to go to a shooting situation," Mattis added.

"These are issues that are longstanding in some cases. ... We're going to have to recalibrate and move these back to a way (where) we solve them politically and work them out with compromised solutions."

Baghdad has taken a series of punitive measures to isolate the autonomous Kurdish region since it overwhelmingly voted for independence on 25 September, including banning international flights from going there.

Iraqi Prime Minister Haider al-Abadi has rejected any discussion of the Kurds' longstanding demands to incorporate Kirkuk and other historically Kurdish-majority areas into their autonomous region until the independence vote is annulled.