Iraqi and Kurdish forces exchanged artillery fire early Monday south of the city of Kirkuk, after central government forces began a "major operation" to take control of a Kurdish military base and oil fields.

Iraqi forces said they had seized an oil field during the operation, which follows soaring tensions over an independence referendum.

Iraq's Joint Operations Command said the forces took over the Baba Gargar oil field, one of six in the disputed Kirkuk region, as well as the headquarters of a public oil company.

Shortly before, state television announced that government troops had taken "large areas" of the province from Kurdish peshmerga fighters "without fighting", although military sources on both sides reported exchange of Katyusha rocket fire to the south of the provincial capital.

Iraqi Prime Minister Haider al-Abadi, who said this week that he was "not going... to make war on our Kurdish citizens", has "given orders to armed forces to take over security in Kirkuk," state television said.

Iraqi troops will "secure bases and government facilities in Kirkuk province" the government said. They are aiming to retake military bases and oil fields which Kurdish peshmerga fighters took in 2014 during the fightback against the Islamic State jihadist group.