A war between U.S. allies could erupt in Iraq

Iraqi forces clashed with Kurdish fighters Monday after Baghdad launched a push to recapture the oil-rich northern city of Kirkuk – an offensive that threatens outright war between the two U.S.-backed factions.

Iraqi Prime Minister Haidar al-Abadi ordered the assault late Sunday, calling for Iraqi soldiers to “impose security” on the Kurdish-controlled city to preserve national unity.

Regional tensions have escalated in recent weeks after Kurds voted for independence from Iraq in a September referendum.

Iraqi state television said Monday that “vast areas” of territory surrounding Kirkuk had been seized, including oilfields and the city’s airport. Kurdish officials disputed this claim.

Inside Kirkuk, hundreds of armed residents have taken up positions to defend themselves, with fighting reaching the edge of the city.

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Journalists reported large, long queues of traffic as many residents fled.

Kurdish officials said Iraqi government forces and Iranian-backed militia attacked positions of the Kurdish peshmerga fighting force on two fronts south of Kirkuk, using U.S. military equipment.

They said the peshmerga had destroyed at least five U.S. Humvees, and would “continue to defend Kurdistan, its peoples and interests.”

“This was an unprovoked attack,” the statement added.

Exchanges of rocket fire were reported south of Kirkuk, with a local security source telling Agence France-Presse that some Kurdish fighters were injured.

Washington, which has been desperate to prevent tensions between its allies from boiling over into another Middle East conflict, said it was “very concerned.”

“We are monitoring the situation in Kirkuk closely and are very concerned by reports of a confrontation,” said a State Department official. “We are engaged with all parties in Iraq to de-escalate tension.”

The United States trains and equips both the Iraqi Army and Kurdish forces as part of its efforts to defeat the so-called Islamic State. Despite being a key ally of the Kurds, Washington has urged them not to push for independence, fearful of disrupting the campaign against ISIS, which is on the brink of being dislodged from its last Iraqi strongholds.

Kirkuk, an ethnically mixed city of about a million people in northern Iraq, is outside the territory held by the Kurdistan Regional Government. But it has been under the control of Kurdish forces for three years, and – despite Baghdad’s claims on the city – was included in the recent referendum on Kurdish independence. Peshmerga forces recaptured the city from ISIS in 2014 after Iraqi forces fled.

The Kurdish Regional Government has been locked in a standoff with Baghdad since the Sept. 25 independence referendum. Iraq says the vote was unconstitutional and should be annulled, while the Kurds have called for dialogue.