BAGHDAD: The military operation launched by Iraq's central government against Kurdish peshmerga fighters is rooted in a long-standing dispute over territory stretching from the Syrian border to the frontier with Iran.
The disputed territory, located south of Arbil, Sulaimaniyah and Dohuk provinces, is more than 1,000 kilometres long (620 miles), covers 37,000 square kilometres (14,000 sq miles), and home to an estimated 1.2 million Kurds.
The three provinces in the rugged, mountainous north of Iraq form the Kurdish region which has been autonomous since 1991.
Apart from the oil-rich province of Kirkuk, the main bone of contention between Baghdad and the Kurds, the disputed territory also includes parts of Salaheddin, Nineveh and Diyala provinces.
Iraqi Kurdistan, as recognised by Baghdad, is home to 5.5 million people and covers 75,000 square kilometres.
It became autonomous after the 1991 Gulf War over Kuwait, as Western powers intervened to protect the Kurds against an onslaught by the forces of dictator Saddam Hussein.
The region gained formal autonomy in 2005 under a constitution which set up a federal republic in Iraq.
For the Kurds, the autonomous region enshrined in the constitution falls short of their historical claims to a larger region also including Kirkuk and its oil fields.
Kurdish peshmerga forces have been in sole control of a chunk of Kirkuk province since federal forces withdrew when faced with an offensive by the Islamic State group in 2014.
They also moved into other disputed areas.
In stages, the peshmerga took control of 23,000 square kilometres across Kirkuk, Nineveh, Salaheddin and Diyala provinces.
They also hold the Makhmur region, which the Kurds claim as part of Arbil province although Iraqi authorities in the 1990s placed it under the jurisdiction of Nineveh.
Kurdish forces, key allies in the US-backed offensive against IS, are now refusing to surrender positions they took during the fightback against the jihadists.
Ties between Baghdad and Iraqi Kurdistan have been strained since the Kurds held a September 25 independence vote, including in Kirkuk, in defiance of the central government.