Kirkuk: Who's fighting in Iraq's Kurdish-controlled province?

Only a few shots were fired, but Iraq's decision to send in armed forces into the Kurdish-controlled province of Kirkuk and bring it back into the fold has heightened tensions in the Middle East nation. Who's on who's side? And where is the territorial dispute going? DW takes a look at the actors and their motives.

In 2014, Kurdish forces went into Kirkuk to fill in the void left behind after Iraq's army collapsed from the "Islamic State's" military campaign. But three years later, the Iraqi military has been rebuilt and ridden a wave of victories against the notorious militant group. They're the main instrument of hard power for the Iraqi government as Baghdad fights for control of the oil-rich province.

Even during the liberation of Mosul, the Iraqi army was backed by the Popular Mobilization Units – an alliance of mostly Shiite militias. The Popular Mobilization Units joined the Iraqi army when it advanced on Kurdish-controlled positions in and around the city of Kirkuk. Kurdish politicians have lashed at the units, saying they're serving Iran's goal to destabilize the region.

The Patriotic Union of Kurdistan (PUK) is one of the main opposition political parties in Iraqi Kurdistan. Since the first Gulf War, the PUK has jointly administered Iraqi Kurdistan with the Kurdistan Democratic Party (KDP). Both the PUK and KDP have their own peshmerga forces. In Kirkuk, PUK peshmerga fled the city, leaving it virtually unopposed to Iraqi forces.

The Kurdistan Democratic Party (KDP) led by Iraqi Kurdistan President Masoud Barzani is the ruling political party in Iraqi Kurdistan's parliament. Despite warnings from the central government, it was the KDP's Barzani who vowed to move forward on the independence referendum, infuriating Baghdad. KDP peshmerga fighters – like the PUK fighters – fled Kirkuk when Iraqi forces advanced on the city.

The Kurdistan Workers' Party (PKK) was born in the 1970s out of an ambitious dream to create a Marxist-Leninist state in the Middle East to be called Kurdistan. In the 1980s, the group launched a bloody insurgency against the state of Turkey. While considered unwelcome in Iraq, the PKK has links with Iraq's Patriotic Union of Kurdistan (PUK) – and likely appeared in Kirkuk to back them.