The video shows PKK militants carrying photos of PKK leader Abdullah Ocalan and the militant group’s flag.

The Iraqi government on Sunday accused authorities of the Kurdistan Regional Government (KRG) of bringing PKK militants to the disputed oil province of Kirkuk, saying it considered the move as a "declaration of war."

Iraq's National Security Council, headed by Prime Minister Haider al-Abadi, said in a statement that the presence of "fighters not belonging to the regular security forces in Kirkuk" was a "dangerous escalation."

"It is impossible to remain silent" when faced with "a declaration of war towards Iraqis and government forces," the statement said, adding, "The central government and regular forces will carry out their duty of defending the Iraqi people in all its components including the Kurds, and of defending Iraq's sovereignty and unity."

Iraq launched the operation in the oil-rich region on Sunday to retake it amid simmering tensions between the central government in Baghdad and the KRG over a recent controversial referendum on the secession of the semi-autonomous Iraqi Kurdish region.

The plebiscite took place on September 25, sparking strong objection from Baghdad. Iraq’s neighbors and the international community also voiced concerns about the repercussions of the vote, which was only supported by Israel.

Kirkuk, with some 10 percent of Iraq’s oil reserves, has long been contested by Baghdad and Erbil.