Iraqi security forces on Monday gained more ground, including a gas facility, in the multi-ethnic province of Kirkuk with the aim of taking control of the disputed areas that were seized by the Kurdish force in 2014, the Iraqi military said.

The troops captured several areas in south and west of the city of Kirkuk, including the gas installation, a nearby oil refinery, a power station and the village of Yaiyji in west of Kirkuk, in addition to an industrial area and two crossing points toward Kirkuk city in south and southwest of the city, the Joint Operations Command (JOC) said in a statement.

During the day, the troops were still pushing into new areas around the city of Kirkuk, some 250 km north of Baghdad, the statement said.

Earlier in the day, Iraqi Prime Minister Haider al-Abadi ordered government forces to enter the oil-rich Kirkuk province in northern Iraq to regain control of the disputed areas claimed between Baghdad and the Kurdish semi-autonomous region.

Iraq's Counter-Terrorism Service (CTS), Federal Police forces and the 9th Armored Division have been deployed in some areas in Kirkuk province, a statement by Abadi's office said.

The troops are pushing to surround the city of Kirkuk to regain control of some military bases, including the huge al-Hurriyah military airbase and the oil fields, the statement said.

It said the deployment process went smoothly in the first hours, but local media reports said that sporadic clashes erupted before dawn between the Iraqi forces and the Kurdish forces, known as Peshmerga, in the industrial area, a few kilometers outside the southern edge of Kirkuk city.

Abadi, also the commander-in-chief of Iraqi forces, required government forces to cooperate with local people and the Kurdish forces of Peshmerga to maintain social stability and security in Kirkuk, according to the statement.

For his part, regional President Masoud Barzani urged Peshmerga not to start the fire with the Iraqi forces, but to keep ready if they advance toward the Kurdish defensive lines, the Kurdish Rudaw media network reported.

Disagreements between Baghdad and the Kurdish regional government have been running high for years. The ethnic Kurds consider the northern Kirkuk province and parts of Nineveh, Diyala and Salahudin provinces as disputed areas and want them to be incorporated into their region, a move fiercely opposed by the Arabs and Turkomans and by the central government in Baghdad.

The areas are mostly under the control of Peshmerga, but in small areas like Tuz-Khurmato, there is a mixed presence of federal forces and the Peshmerga.

Tensions are escalating between Baghdad and the region of Kurdistan after the Kurds held a controversial referendum on the independence of the Kurdistan region and the disputed areas.

The independence of Kurdistan is opposed not only by the Iraqi central government, but also by most other countries as it would threaten the integrity of Iraq and undermine the fight against Islamic State militants.

Iraq's neighboring countries, especially Turkey, Iran and Syria, fear that the Iraqi Kurds' pursuit of independence threatens their territorial integrity, as a large Kurdish population lives in those countries.