Iraqi forces have demanded that Kurdish troops withdraw from oil fields and military bases around the contested city of Kirkuk, Kurdish officials and a senior militia leader said Friday, leading to a tense standoff around the city.

Kurdish peshmerga soldiers rallied to protect Kirkuk on Thursday night, as Interior Ministry troops and Shiite militias mobilized nearby. Volunteer and retired fighters bolstered the lines. Several positions were taken over by Iraqi forces, however, with Kurdish officers saying they received orders to withdraw.

The Kirkuk area, with about 10 percent of Iraq’s oil reserves, has long been contested by the central government in Baghdad and Kurdish authorities in Irbil, but the province has become even more of a flash point since the Kurdistan region voted in favor of independence in a referendum last month.