Tensions have escalated between Iraq and its northern autonomous Kurdish region since Kurdish voters overwhelmingly backed independence in a non-binding referendum more than two weeks ago.

Here are the key developments:

- Millions vote -

Despite weeks of threats and warnings, the vote goes ahead on September 25 with more than 12,000 polling stations opening for 5.3 million registered voters.

It is held in the three provinces of Iraqi Kurdistan -- Arbil, Sulaimaniyah and Dohuk -- as well as in disputed border areas such as the oil-rich province of Kirkuk.

Baghdad says the vote is "illegal" and the United States warns it will increase instability.

Neighbouring Turkey, concerned the vote could stoke separatist aspirations among its own Kurdish minority, warns the Iraqi Kurds they will face sanctions over the vote.

Iran, which has similar fears, has already announced it is stopping all flights to and from Iraqi Kurdistan.

Iraqi Prime Minister Haider al-Abadi the following day gives authorities in Kurdistan 72 hours to hand the central government control of airports, warning he will otherwise ban international flights to and from Kurdistan.

- A massive 'yes' -

The official results released on September 27 show that more than 92 percent of voters back statehood. Turnout is over 72 percent.

Iraqi Kurd leader Massud Barzani says there will be no immediate declaration of independence but calls for negotiations.

But Abadi demands the vote is annulled. "We will never hold talks based on the results of the referendum," he says. "We will impose Iraqi law in the entire region of Kurdistan."

Ankara and Washington say they are willing to facilitate talks to calm soaring tensions.

- Flights cut, screws tighten -

The Kurdish region's direct air links with the outside world are indefinitely cut in the evening of September 29. Foreigners have already started leaving while they can.

Humanitarian, military and diplomatic planes are excluded from the ban.

The United States says the same day that it does not recognise the vote.

"The vote and the results lack legitimacy and we continue to support a united, federal, democratic and prosperous Iraq," Secretary of State Rex Tillerson says.

On October 2, Iranian and Iraqi forces conduct joint military exercises with tanks and infantry reported around 250 metres (yards) from the border with the Kurdistan region.

Iran has meanwhile embargoed exports and imports of fuel products to and from Iraqi Kurdistan "until further notice", media report.

An Iraqi court on October 11 orders the arrest of the chairman and two other members of the commission that organised the independence referendum.

- Soldiers deployed -

There is alarm as Kurdish peshmerga forces on October 12 block roads from Iraqi Kurdistan to Iraq's second city Mosul in response to an increase in deployments and movements of Iraqi forces near the front line.

Kurdish authorities say they have received "dangerous messages" that Iraqi government forces and allied paramilitary units are preparing an assault.

But Abadi denies an attack is imminent. "Our duty is to preserve the unity of our country, to implement the constitution, and to protect citizens and national forces," he says.

On October 13, the Iraqi army launches an operation to take Kurdish-held positions around the provincial capital of Kirkuk, which has a Kurdish majority and took part in the contested referendum.

A senior Kurdish official says thousands of heavily armed fighters had been deployed to resist the offensive "at any cost".

He calls for international intervention.

Source: AFP