Iraqi government forces have captured key installations outside the disputed city of Kirkuk from Kurdish fighters, BBC reports.
A military statement said units had taken control of the K1 military base, the Baba Gurgur oil and gas field, and a state-owned oil company's offices.
Baghdad said the Peshmerga had withdrawn "without fighting", but clashes were reported south of Kirkuk.
The operation was launched a month after the Kurdistan Region held a controversial independence referendum.
Iraq's prime minister has said the vote - in which residents of Kurdish-controlled areas, including Kirkuk, overwhelmingly backed secession - was unconstitutional.