The statement listed facilities in Kirkuk that the army had appropriated from Kurdish Peshmerga forces (loyal to northern Iraq's Kurdish Regional Government), who reportedly withdrew from the city and its outskirts before the Iraqi army advance.

These facilities include Kirkuk's main airport, the Northern Petroleum Company, the K1 military base, the Mulla Abdullah oil refinery and the Tikrit Bridge, among others.

Earlier Monday, Iraqi forces reportedly assumed control over central Kirkuk's main government headquarters, according to a local police source.

"A large contingent of Iraqi Federal Police has entered the government headquarters [in Kirkuk] over which they have raised the Iraqi flag," Kirkuk Police Captain Hamed al-Obaidi told Anadolu Agency.

The Iraqi authorities have also reportedly imposed a citywide curfew in Kirkuk, set to expire at 7.00 a.m. (0400GMT) Tuesday morning.

Prime Minister Haider al-Abadi, meanwhile, has also ordered Iraqi security forces to secure the majority-Turkmen district of Tuz Khurmatu in Iraq's Saladin province north of Baghdad, according to a statement released by al-Abadi’s office.

Late Sunday, Iraqi forces -- including army troops, Federal Police units and Hashd al-Shaabi fighters -- began their advance towards ethnically-diverse Kirkuk with a view to seizing strategic sites and facilities.

Since the 2003 U.S.-led invasion of Iraq, oil-rich Kirkuk has remained the subject of dispute between the central government in Baghdad and the Erbil-based Kurdish Regional Government (KRG).

Answerable to KRG President Masoud Barzani, the Peshmerga took control of Kirkuk after the Iraqi army fled before the Daesh terrorist group’s onslaught in 2014.

Tension has mounted steadily between Baghdad and the KRG since Sept. 25, when Iraqis in KRG-controlled areas -- and in several disputed areas, including Kirkuk -- voted on whether or not to declare regional independence.

The illegitimate referendum had faced strong opposition from most regional and international actors (including the U.S., Turkey and Iran), who warned that the poll would distract from Iraq’s fight against terrorism and further destabilize the region.