The Kurdish regional head has vowed never to return to "the failed partnership" with Baghdad, ahead of Monday's independence vote which Iran, Iraq and Turkey all oppose. Earlier, Iran halted flights to and from the area.
All air traffic between Iran and the international airports of Irbil and Sulaymaniyah, located in Iraqi Kurdistan, was halted on Sunday at Baghdad's behest.
The moves came in retaliation to the autonomous Kurdistan Regional Government's (KRG) planned referendum on the secession of northern Iraq's Kurdish region on Monday.
"At the request of the central government of Iraq, all flights from Iran to Sulaymaniyah and Irbil, as well as all flights through our airspace originating from the Kurdistan region, have been stopped," the spokesman for Iran's Supreme National Security Council, Keivan Khosravi, was quoted as saying.
Iraq's government has decried the referendum as unconstitutional and fears it could lead to unrest in the already volatile region. Turkey and Iran, which also have sizeable Kurdish populations, fear the vote will stoke separatist aspirations within their borders as well.
Turkish Prime Minister Binali Yildirim denounced the referendum on Sunday, warning that it would "further fuel existing instability, lack of authority and chaos in the region." However, Ankara has yet to impose any retaliatory measures.
Kurdistan Regional Government President Masoud Barzani said, however, that Iraq's Kurds will not be deterred from holding the referendum.
"We will never go back to the failed partnership" with Baghdad, Barzani said, adding that the Iraqi government has become a "theocratic, sectarian state."
UN calls for vote delay
While Iran is also desperate to diffuse secessionist aspirations among its Kurdish population, its regime has also supported Shiite groups that have ruled over key security and government positions in Iraq ever since the US-led invasion in 2003 toppled the Saddam Hussein regime.
Meanwhile, the United Nations, US and Britain have all called on the KRG to delay the vote amid fears that it could further destabilize the region. Those calls, however, have fallen of deaf ears. It remains unclear what affect the vote could have on US backing of Kurdish military groups in the fight against the so-called "Islamic State" group in Syria.
Read more: The Middle East's complex Kurdish landscape
However, despite regional and international opposition, Monday's independence referendum is nevertheless scheduled to go ahead and expected to result in a comfortable "Yes" vote. While the vote is not binding, the KRG hopes it will give it a mandate to negotiate the secession of an autonomous Kurdish region from Baghdad and the neighboring countries.
Iranian and Turkish security forces mobilize
A day ahead of the vote, Iran's elite Revolutionary Guards also conducted a series of military drills on the border with Iraqi Kurdistan. Officials, however, insisted that these were part of the country's annual event marking the beginning of the 1980-1988 war with Iraq and that they had nothing to do with Monday's plebiscite.
Clashes between Iranian security forces and the Iranian Kurdish militants based in Iraq are fairly common in the region, with Kurdish separatists regularly carrying out cross-border attacks on Iranian forces.
Turkish fighter jets on Saturday also targeted gun positions, caves and shelters used by militants from the Kurdistan Workers' Party (PKK). Such airstrikes against the separatist militant group, which is based in northern Iraq, are also common.
The PKK launched its insurgencyagainst the Turkish government in 1984. The conflict has since claimed some 40,000 lives.
dm/cmk (AFP, Reuters, dpa)