Iraq's government forces and allied militia captured the major Kurdish-held city of Kirkuk on Monday in an audacious lightning offensive, responding to a Kurdish independence referendum with a move that drastically changes the balance of power in the country.
A convoy of armored vehicles from the elite U.S.-trained Counter-Terrorism Force seized provincial government headquarters by afternoon less than 24 hours after the operation began.
Neither side gave a casualty toll for the operation, but some have estimated about 10 Kurdish Peshmerga fighters and several Iraqi soldiers were killed in an overnight clash south of the city. No other serious fighting was reported.
The overnight advance was the most decisive step Baghdad has taken yet to block the independence bid of the Kurds, who have governed an autonomous tract of northern Iraq since the fall of Saddam Hussein in 2003.
Three weeks ago, the region voted to secede in a referendum that the Iraqi government refused to recognize.
The move came shortly after Iraq’s central government accused Kurdistan Regional Government authorities of bringing militants from Turkey's Kurdistan Workers' Party or PKK to Kirkuk, saying it considered the move a "declaration of war."
As the Iraqis plunged deep into the disputed region, Kurdish operators briefly shut some 350,000 barrels per day of oil output at two large Kirkuk fields, citing security concerns, oil ministry sources on both sides said. Production resumed shortly thereafter following an Iraqi threat to seize fields under Kurdish management.
The short suspension in production helped push up world oil prices as the shutdown represented more than half of total Kurdish output. By some estimates, the region is home to about ten percent of Iraq's reserves.
Baghdad described its army's advance as largely unopposed and urged the Kurdish population and the Peshmerga to cooperate in keeping the peace. The Peshmerga warned that Baghdad would pay "a heavy price" for triggering "war on the Kurdistan people".
Iraqi Prime Minister Haidar al-Abadi ordered that the national flag be hoisted over Kirkuk and other disputed areas. A dozen Iraqi armored vehicles arrived at the provincial government headquarters in Kirkuk and took up positions nearby, alongside local police. They pulled down the Kurdish flag and left the Iraqi flag flying.
"This day should become a holiday, we're so happy to have gotten rid of Barzani's party," said a man celebrating on a motorbike, waving the blue-and-white flag of Iraq's Turkmen, referring to the Kurdish leader Masoud Barzani.
U.S. officials called for calm on both sides, seeking to avert an all-out conflict between Baghdad and the Kurds that would open an entirely new front in Iraq's 14-year-old civil war and potentially draw in regional powers such as Turkey and Iran.
"We oppose violence from any party, and urge against destabilizing actions that distract from the fight against Daesh and further undermine Iraq's stability," said Pentagon spokeswoman Laura Seal.
"We continue to support a unified Iraq…Despite the Kurdistan Regional Government's unfortunate decision to pursue a unilateral referendum, dialogue remains the best option to defuse ongoing tensions and longstanding issues, in accordance with the Iraqi constitution," she added.
The Baghdad central government considers the Sept. 25 Kurdish independence referendum illegal, especially as it was held not just in the autonomous KRG region but in Kirkuk and other adjacent areas that Peshmerga forces occupied after driving out Islamic State militants in 2014.
The Kurdish secession bid was strongly opposed by neighbors Iran and Turkey. Washington, long seen as an ally of Iraq's Kurds, pleaded vainly for them to halt a vote that could break up the country.