BAGHDAD (Reuters) - Kurdish authorities said on Friday they had sent thousands more troops to Kirkuk to confront “threats” of Iraqi military attack, but also slightly pulled back defense lines around the disputed oil-producing area to ease tensions.

A Kurdish Peshmerga fighter is seen in the Southwest of Kirkuk, Iraq October 13, 2017. REUTERS/Ako Rasheed

The Baghdad central government has taken a series of steps to isolate the autonomous Kurdish region since its overwhelming vote for independence in a Sept. 25 referendum, including banning international flights from going there.

Baghdad’s tough line, ruling out talks sought by the Kurds unless they renounce the breakaway move, is backed by neighbors Turkey and Iran - both with their own sizable Kurdish minorities, and in Turkey’s case, a long-running Kurdish insurgency.

Tens of thousands of Kurdish Peshmerga soldiers have been stationed in and around Kirkuk for some time and another 6,000 have arrived since Thursday, Kosrat Rasul, vice president in the Kurdistan Regional Government (KRG), said.

In Washington, U.S. Defense Secretary Jim Mattis said on Friday the situation had the full attention of the United States, which was working to ensure it does not escalate.

“We can’t turn on each other right now. We don’t want this to go to a shooting situation,” Mattis said. “These are issues that are longstanding in some cases ... We’re going to have to recalibrate and move these back to a way (in which) we solve them politically and work them out with compromised solutions.”

The KRG’s Security Council expressed alarm late on Thursday at what it called a significant Iraqi military buildup south of Kirkuk, “including tanks, artillery, Humvees and mortars.””These forces are approximately 3 km (1.9 miles) from Peshmerga forces. Intelligence shows intentions to take over nearby oilfields, airport and military base,” it said in a statement.

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Kurdish security sources later said that the Peshmerga had shifted their defense lines by 3 km (1.9 miles) to 10 km south of Kirkuk to reduce the risk of clashes with Iraqi forces, which then moved into some of the vacated positions without incident.

The area from which the Peshmerga withdrew is populated mainly by Shi’ite Muslim Turkmen, many of whom are loyal to the Shi’ite led-government in Baghdad and affiliated with Iranian-backed political parties and paramilitary groups.

An Iraqi military spokesman said military movements near Kirkuk aimed only to “inspect and secure” the nearby region of Hawija recaptured from Islamic State militants a week ago.

Iraqi Prime Minister Haider al-Abadi has repeatedly denied any plans to go further and actually attack the territory.

Kirkuk, a city of more than one million people, lies just outside KRG territory but Peshmerga forces deployed there in 2014 when Iraqi security forces collapsed in the face of an Islamic State onslaught. The Peshmerga deployment prevented Kirkuk’s oilfields from falling into jihadist hands.

KRG Prime Minister Nechirvan Barzani urged the United States, the European Union and the U.N. Security Council “to rapidly intervene to prevent a new war.”

Germany, which traditionally has good relations with both Baghdad and the KRG, called for measures to defuse tensions.

“We would like to ask them to meet those responsibilities and not to escalate the conflict,” German government spokesman Steffen Seibert told reporters in Berlin.

President Tayyip Erdogan’s spokesman said on Thursday Ankara would gradually close border crossings with northern Iraq in coordination with the central Iraqi government and Iran.

Turkish Prime Minister Binali Yildirim is expected in Baghdad on Sunday for talks with Abadi.