ANKARA/BAGHDAD (Reuters) - Turkish tanks carried out drills at the Iraqi border on Monday, the army said, a week before a referendum across that frontier on Kurdish independence that Ankara has called a threat to its national security.

The exercises came as Turkey, the central government in Baghdad and their shared neighbor Iran all stepped up protests and warnings about the looming plebiscite in semi-autonomous Kurdish northern Iraq.

Iran, which like Turkey fears fuelling separatism in its own Kurdish population, warned of unspecified consequences if the vote went ahead.

Turkey’s Prime Minister Binali Yildirim said any threats from inside or outside its territory would face immediate retaliation. The military command released pictures of the tanks speeding along roads and kicking up dust during exercises.

Iraq’s Supreme Federal Court ordered Kurdistan region to suspend the vote, Prime Minister Haider al-Abadi’s office said. Baghdad, its neighbors and Western powers fear the referendum could distract attention from the fight against Islamic State militants across the region.

But the Kurdish leadership showed no sign of bowing to pressure to call off the vote, including from the United Nations - which urged Erbil to resolve disputes with Baghdad over land and power sharing through dialogue.

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TANKS, MISSILES

In Turkey, around 100 military vehicles, mostly tanks, took part in the drill near the Habur border gate, a crossing point into Iraq, the private news agency Dogan said. Vehicles carrying missiles and howitzers also participated.

Turkish military sources said the drill was due to run until Sept. 26, a day after the planned Kurdish referendum.

Turkey has not spelt out what response it might take if the referendum goes ahead. It has brought forward meetings of the cabinet and its national security council to Friday, three days ahead of the vote, to look again at the situation.

Separately, Turkey’s military said it carried out an air strike in northern Iraq on Monday and that “four terrorists were neutralized”. Turkish forces often launch cross-border attacks they say target members of the outlawed Kurdish PKK group, which has waged an insurgency in southern Turkey for three decades.

“Those who are chasing dreams in Syria and Iraq should know very well that any attempt that threatens our national security, from inside or outside our borders, will be immediately retaliated in kind,” Prime Minister Yildirim said in a speech in the southern Turkish town of Sanliurfa.

Kurdish forces have, with U.S. backing, been in the forefront of the battle against Islamic State in Iraq and Syria. The Kurdish involvement in Syria strains relations between Washington and Ankara.

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The Iraqi Supreme Federal Court approved Prime Minister Abadi’s demand to consider “the breakaway of any region or province from Iraq as unconstitutional”, his office said in a statement.

The court is responsible for settling disputes between Iraq’s central government and regions including Kurdistan, but has no means to implement its rulings in the Kurdish region which has its own police and government, led by Massoud Barzani.

Iran issued a veiled warning to the Kurds that their security could be affected if Iraq’s unity was threatened.

“Any damage to this strategic principle would lead to the revision of and serious alteration in the existing cooperation between Iran and Iraq’s Kurdistan region,” said Ali Shamkhani, the secretary of Iran’s Supreme National Security Council, according to state-run Press TV.

Turkey’s protests in the build-up to the vote had been relatively muted. It has built good relations with Barzani’s semi-autonomous Kurdish administration in northern Iraq, founded on strong economic links as well as Ankara and Erbil’s shared suspicions of other Kurdish groups.

The Kurdish Regional Government, led by Barzani's KDP party,exports hundreds of thousands of barrels of oil per day to worldmarkets via Turkey and said on Monday that Russian oil major Rosneft ROSN.MM would invest in pipelines in the Kurdish region to export gas to Turkey and Europe.