They fear fully-fledged independence for the Kurds of northern Iraq could embolden Turkey's own Kurdish minority, which is estimated to make up around a quarter of its population of nearly 80 million.

The idea of a Kurdish state -- even one outside Turkey's borders -- is anathema not only to Turkey's ultra-right nationalists but also to its conservatives as well as its secular opposition.

Turkey has warned the Iraqi Kurds they risk paying a "price", evoking possible sanctions over the non-binding vote. But it has been notably circumspect over what this might mean.

Ankara's displeasure over the referendum, which is planned for September 25, is shared not only by the government in Baghdad but also by its sometimes prickly neighbour Iran, not to mention Turkey's Western allies in NATO.

Turkey, which staunchly opposes Kurdish statehood, is far from alone in its rejection of an independence referendum in northern Iraq but it remains unclear whether this will translate into concrete action.

Left without a state of their own when the borders of Europe and the Middle East were redrawn during the collapse of the Ottoma

n Empire after World War I, the Kurds see themselves as the world's largest stateless people.

They live in an area spanning Turkey, Syria, Iran and Iraq.

By far the biggest population is in Turkey, which since 1984 has waged a campaign to defeat the outlawed Kurdistan Workers' Party (PKK), which initially sought to create a breakaway state in its southeast.

'Deep suspicions'

But millions of Kurds also live in Iran -- which itself fought sporadic insurgent actions by groups like the Party of Free Life of Kurdistan (PJAK) -- and Tehran and Ankara have often cooperated to stem the rise of Kurdish nationalism.

After an unprecedented visit to Ankara earlier this month by Iran's chief of staff, President Recep Tayyip Erdogan said the two sides could launch joint operations against Kurdish militants although this was denied by Tehran.

Ali Vaez, senior Iran analyst at the International Crisis Group, said Tehran and Ankara had a shared interest in preserving Iraq's territorial integrity and also enjoyed extensive communication channels.

But while mainly Shiite Iran and Sunni Turkey had the capability to jointly pressure the Iraqi Kurds, a regional rivalry dating back to their imperial eras risked getting in the way.

"Though both have attempted to build on common concerns, deep suspicions about the other's ambitions to benefit from the chaos have stopped them from reaching an arrangement that could lower the region's flames," Vaez told AFP.

'Significant damage'

A Kurdish woman dances in front of a fire during the New Year festival of Newroz in Turkey, where Kurds make up around a quarter of its population of nearly 80 million (photo by: BULENT KILIC/AFP/File)

Despite Turkey's anger over the presence of PKK bases in northern Iraq, Ankara has formed a close economic relationship with the Kurdistan Regional Government (KRG) in recent years, giving it immense potential leverage over Arbil.

Iraqi Kurdistan has become one of Turkey's largest export markets, with prominent Turkish consumer goods and furniture brands ubiquitous on the streets of its m

ajor cities.

Meanwhile, Turkey provides the sole transit link for crude oil exports from the KRG through a pipeline via its southern port of Ceyhan.

"Turkey is in a position to inflict significant damage to the Iraqi Kurds if it wants to," said David Romano, professor of Middle East politics at Missouri State University.

But he said cutting economic ties with the Iraq Kurds would risk some $10 billion a year in trade, oil and gas imports and transit fees which are crucial to Turkey's own Kurdish-dominated southeast.

"Turkey makes a lot of noises against the referendum, but it's mainly to assuage the Turkish nationalist component of the ruling party's base," he argued.

With conspicuous timing, Turkey this week launched war games next to its border with the KRG but has made no concrete threat of military intervention.

'Common ground' with Assad

The only clear backing for the referendum within the region has come from Israel, a longstanding if low-key backer of Kurdish ambitions as a non-Arab buffer against the Jewish state's arch enemy Iran.

Erdogan's spokesman Ibrahim Kalin noted that not a single country, "other than Israel", backed the referendum bid.

Gulf kingpin Saudi Arabia on Wednesday urged the KRG leadership to scrap the plan, warning it risked sparking further regional crises.

According to some analysts, rising Kurdish nationalism across the region could even prompt Turkey to find common cause with its prime foe of the last half decade, the Syrian regime of President Bashar al-Assad.

Both Ankara and Damascus want to head off the prospect of an autonomous Kurdish region in northern Syria neighbouring the KRG and run by the Peoples' Protection Units (YPG) -- a Kurdish militia Turkey sees as a terror group and a branch of the PKK.

Aaron Stein, resident senior fellow at the Atlantic Council's Rafik Hariri Center, said Ankara had "de-prioritised" the issue of Assad "in favour of efforts to keep Syria united."

Turkey has now foun

d "common ground" with the Assad regime in countering the YPG, said Gonul Tol, director of the Middle East Institute's Center for Turkish Studies.