Iraqi government forces have captured some key facilities in Kirkuk, an oil-rich region in northern Iraq that is effectively controlled by the Kurds.
The military said in a statement on Monday that its troops advanced into Kirkuk and took control of one of the oil fields, a power plant and a Kurdish military base.
The Kurdish autonomous government said its forces destroyed at least 5 Iraqi military vehicles in returning fire against Iraqi tanks.
Iraqi Prime Minister Haider al-Abadi said in a statement that it is his duty to protect national unity. He stressed that the offensive in the region is not aimed at hurting civilians.
The Kurdish and Iraqi central governments have disputed the jurisdiction of Kirkuk. The Kurds have deployed troops and controlled the region for 3 years, since the Iraqi military withdrew while the Islamic State militant group was expanding its foothold there.
The Kurds are reportedly withdrawing their forces stationed there to avoid fighting with the Iraqi military. But observers fear possible major clashes.
The conflict between the 2 governments has deepened since the autonomous government held a referendum last month. The Kurds say the results show their will to gain independence from the country. But the central government has not recognized the referendum.