FACTBOX: Tension over Kurds on Turkey-Iraq border

(Reuters) - Major powers sought on Saturday to reduce tensions on the Turkish-Iraqi border and prevent any large-scale incursion by Turkey's military in pursuit of Kurdish militants based in northern Iraq.

A conference in Istanbul was meant to focus on improving security in Iraq but has been overshadowed by the fall-out from PKK guerrilla attacks launched from Iraq and concerns for regional stability.

Following are some of the details behind the tension:

* KURDISH HISTORY:

-- The Kurds are a non-Arab, mainly Sunni Muslim people, speaking a language related to Persian and living in a mountainous area straddling the borders of Armenia, Iraq, Iran, Syria and Turkey.

-- For most of their history they have been subjugated. In modern times Iran, Iraq and Turkey have resisted an independent Kurdish state and the Western powers have seen no reason to help establish one.

-- Kurdish nationalism stirred in the 1890s when the Ottoman Empire was on its last legs. The 1920 Treaty of Sevres, which imposed a settlement and colonial carve-up of Turkey after World War One, promised them independence.

-- Three years later, Turkish leader Kemal Ataturk tore up the treaty. Kurdish revolts in the 1920s and 1930s were put down by Turkish forces. The Kurds were not recognized as a separate people or allowed to speak their language in public.

* FIGHT FOR A HOMELAND:

-- The Kurdistan Workers Party (PKK), named in 1978, took up arms against Turkey in 1984 with the aim of creating an ethnic homeland in the southeast. Since then nearly 40,000 people have been killed in the conflict.

-- The Kurdish language ban was lifted in 1991.

-- PKK leader Abdullah Ocalan was captured in 1999, tried and sentenced to death. That was reduced to life imprisonment in October 2002 after Turkey abolished the death penalty.

-- Fighting eased after Ocalan's capture, leading to a ceasefire and the withdrawal of rebel fighters from Turkey. Ocalan put new emphasis on seeking Kurdish rights through political, rather than armed struggle.

* NORTHERN IRAQ:

-- The Kurds fared little better in northern Iraq where, under a British mandate, revolts were quashed in 1919, 1923 and 1932.

-- Under leader Mustafa Barzani, the Iraqi Kurds waged an intermittent struggle against Baghdad after World War Two.