Iran strongly opposes Monday's Kurdish referendum vote and fears it could fuel separatism among its own Kurds
Iran halted flights to and from Kurdish regions in northern Iraq on Sunday in retaliation for a plan by the autonomous Kurdistan Regional Government (KRG) to hold a referendum on independence. It also started wargames at the Kurdish border.
The air embargo is the first concrete retaliatory measure against Monday's Kurdish referendum which is rejected by the government in Baghdad and by Iraq's powerful neighbours, Iran and Turkey.
Iranian authorities stopped air traffic to the international airports of Erbil and Sulaimaniya, in Iraqi Kurdistan, upon a request from Baghdad, Fars News Agency said.
Tehran and Ankara fear the spread of separatism to their own Kurds. Iran also supports Shia groups who have been ruling or holding key security and government positions in Iraq since the 2003 US-led invasion which toppled Saddam Hussein.
Turkey also said on Sunday its aircraft launched air strikes against Kurdistan Workers' Party (PKK) targets in northern Iraq's Gara region on Saturday after spotting militants preparing to attack Turkish military outposts on the border.
The Kurdistan Regional Government has resisted calls to delay the referendum made by the United Nations, the United States and the UK, which fear it could further destabilise the region.
Iranian state broadcaster IRIB said military drills, part of annual events held in Iran to mark the beginning of the 1980-1988 war with Iraq, are centred in the Oshnavieh border region. The war games will include artillery, armoured and airborne units, it said.
Clashes with Iranian Kurdish militant groups based in Iraq are fairly common in the border area.
Turkey strikes PKK in Iraq
On Saturday, Turkish warplanes destroyed gun positions, caves and shelters used by PKK militants, a military statement issued in Ankara said. Turkey's air force frequently carries out such air strikes against the PKK in northern Iraq, where the group's commanders are based.
Turkey's parliament voted on Saturday to extend by a year a mandate authorising the deployment of Turkish troops in Iraq and Syria.
The PKK launched an insurgency in 1984. More than 40,000 people have been killed in the subsequent conflict. It is designated a terrorist group by Turkey, the United States and the European Union.
The US embassy in Iraq cautioned its citizens that there may be unrest during the referendum, especially in territories disputed between the KRG and the central government such as in the multi-ethnic oil-rich region of Kirkuk.
Three Kurdish Peshmerga fighters were killed and five wounded on Saturday when an explosive device blew up near their vehicle in south Kirkuk, security sources said.
The explosion happened in Daquq, a region bordering areas held by the Islamic State group (IS), the sources said.
IS's ''caliphate'' effectively collapsed in July, when a US-backed Iraqi offensive, in which the Peshmerga took part, captured their northern Iraq stronghold of Mosul.
The group continues to control a pocket west of Kirkuk and a stretch alongside the Syrian border and inside Syria.