ERBIL, Iraq/ANKARA (Reuters) - The last international flight left Erbil airport on Friday as the Baghdad government imposed an air ban on Iraqi Kurdistan in retaliation for an independence vote that has drawn widespread opposition from foreign powers.

An Iraqi Airways plane is seen at the Erbil International Airport in Erbil, Iraq September 29, 2017. REUTERS/Azad Lashkari

Iraq's Kurds overwhelmingly backed independence in Monday's referendum, defying neighboring countries, which fear the vote could lead to renewed conflict in the region. (GRAPHIC: Iraq's Kirkuk region - tmsnrt.rs/2gq0Gk4)

Foreign airlines suspended flights to Erbil and Sulaimaniya in the autonomous region, obeying a notice from the government in Baghdad, which controls Iraqi air space.

Erbil airport was busier than usual as passengers scrambled to catch the last flights out before the ban went into force at 6 p.m. (1500 GMT) on Friday.

Domestic flights are still allowed, so travelers are expected to travel to Kurdistan mostly via Baghdad’s airport, which will come under strain from the extra traffic.

Maintaining the travel curbs is likely to discourage visits by businessmen and Kurdish expatriates, and affect industries including hotels, financial services, transport and real estate.

More than 400 Kurdish travel and tourism companies are directly affected by the flight ban and 7,000 jobs are at risk in the sector, Erbil-based Rudaw TV said.

The Kurdistan Regional Government (KRG), meanwhile, refused to hand over control of its border crossings to the Iraqi government, as demanded by Iraq, Iran and Turkey in retaliation for the independence referendum.

CONTROL OF BORDERS

The Iraqi Defence Ministry said it planned to take control of the borders “in coordination” with Iran and Turkey. The statement did not give more detail or indicate whether Iraqi forces were planning to move toward the external border posts controlled by the KRG from the Iranian and Turkish side.

As the crisis unfolded, Iraq’s top Shi’ite cleric intervened to oppose the secession of the Kurdistan region, adding to pressure on the Kurds in his first directly political sermon since early last year.

Grand Ayatollah Ali al-Sistani asked the KRG to “return to the constitutional path” in pursuing self-determination for the Kurdish people, a representative said in a sermon on his behalf.

“Any attempt to make secession an accomplished fact will lead to undesired consequences affecting Kurdish citizens,” the sermon said.

Turkey, which has already threatened economic sanctions and a military response to any security challenges posed by the referendum result in neighboring northern Iraq, has maintained a drumbeat of opposition to the Kurdish vote.

After talks in Ankara with Russian President Vladimir Putin on Thursday, Turkish President Tayyip Erdogan said the referendum was illegitimate and Russia and Turkey agreed that the territorial integrity of Iraq must be preserved.

Turkey and Russia have strong commercial ties with the semi-autonomous Kurdish region in Iraq. But the vote has alarmed Ankara as it battles a separatist insurgency from its own large Kurdish minority.

OIL LIFELINE

While Turkey has threatened to cut off the Kurds’ oil export lifeline - a pipeline that runs through Turkish territory - it has so far mostly held back from specific action against Iraqi Kurdistan.

Prime Minister Binali Yildirim said Turkey would target only those who had decided to hold the referendum, and would not make civilians pay the price for the vote.

Iran banned the transportation of refined crude oil products by Iranian companies to and from Iraqi Kurdistan.

But a World Bank official said Kurdistan would be able to resist an economic blockade.

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“It is self-sufficient in electricity and fuel supply as it has the oil and gas fields, the refineries and the power stations,” the official said.

“It has also the land and the water resources to sustain a basic subsistence, even if borders are shut completely.”

The autonomous region is the closest the Kurds have come to a state in modern times. But although it has flourished while the rest of Iraq was embroiled in civil war, it may struggle to maintain investment if it is blockaded economically.

The United States, major European countries and nearby Turkey and Iran opposed the referendum as destabilizing at a time when all sides are still fighting Islamic State.

OFFERS TO HELP

Both France and the United States said on Friday that Iraq’s territorial integrity must be maintained, but urged Baghdad not to retaliate.

U.S. Secretary of State Rex Tillerson said in a statement that “the vote and the results lack legitimacy” before going on to urge “calm and an end to vocal recriminations and threats of reciprocal actions”.

French President Emmanuel Macron said the two sides should remain united in their priority to defeat Islamic State and stabilize Iraq, and that any further escalation should be avoided. A source in Macron’s office said Iraqi Prime Minister Haider Abadi had accepted an invitation to come Paris on Oct. 5 for talks on the issue.

The U.S. State Department said Washington was willing to facilitate talks if asked, and the Iraqi Foreign Ministry said the United Nations had also offered its good offices.

The Iraqi parliament urged the Baghdad government to send troops to take control of oilfields held by Kurdish forces.

Baghdad also told foreign governments to close their diplomatic missions in the Kurdish capital Erbil.

The Kurds consider Monday’s referendum to be an historic step in the generations-old quest for a state of their own, while Iraq considers the vote unconstitutional.

They say the referendum acknowledges their contribution in confronting Islamic State after it overwhelmed the Iraqi army.

Iraqi Kurdish leader Masoud Barzani has said the vote is not binding, but meant to provide a mandate for negotiations with Baghdad and neighboring countries over peaceful secession from Iraq. Baghdad has rejected talks.

The Kurds were left without a state of their own when the Ottoman Empire collapsed a century ago, and 30 million Kurds now live spread across Iraq, Turkey, Syria and Iran.