Military commanders in Baghdad said their troops had taken control of an industrial district on the western edge of Kirkuk, as well as a power plant and refinery adjacent to the oil fields outside the city. The military command also said government forces had secured control of a military airport west of the city.
Among the sites the Iraqi forces claimed was a military base known as K-1, northwest of Kirkuk. Iraqi officers interviewed near the base on Sunday said that American forces had used the facility in the past.
K-1 was the main military base in Kirkuk Province for Iraqi government troops when they abandoned their weapons and fled an assault by Islamic State militants.
On Monday, a Kurdish commander from the governing political party in the Kurdistan region said his forces had mounted a counterattack about 15 miles west of the city. He said reinforcements with “sophisticated weapons” had arrived to support Kurdish fighters in the area.
“They are preparing to liberate the area” from Iraqi forces, said the commander, Gen. Mohammed Raiger.
A statement released by the Kurdistan Region Security Council said pesh merga fighters had destroyed five American-supplied Humvees used by Iraqi forces, and would continue to resist them.
“This was unprovoked attack,” the statement said of the government military advance. The council is controlled by the Kurdistan Democratic Party, or K.D.P., led by Mr. Barzani, the region’s president.
But a leader of a rival Kurdish party, the Patriotic Union of Kurdistan, or P.U.K., said the party had agreed to vacate its military positions and hand them over to government forces early Monday morning. Wista Raool, commander of P.U.K. pesh merga forces south of Kirkuk, said the party sought to return the oil fields to the central government.
Mr. Raool accused Mr. Barzani and his party of “stealing” the oil from the central government. Many members of the P.U.K., which maintains its own pesh merga force, opposed the referendum vote because it was spearheaded by Mr. Barzani.
Iraqi military commanders said fighting broke out early Monday between advancing government forces and pesh merga fighters from Mr. Barzani’s faction, just as the P.U.K. forces were handing over their positions. The commanders spoke on condition of anonymity because they were not authorized to speak to journalists.Thoughtful commentary on Kurdish independence included Masoud Barzani's political survival (he is acting as president of the Kurdistan Regional Government (KRG) after his term has expired) as a significant motive for holding the referendum. The PUK reluctantly supported the independence referendum but are not going to fight a war over it.