Turkey is threatening to invade Iraq

As Iraq continues to fracture and Americans are focused on battles between the Sunni-Shiite factions, many forget that the Kurdish areas are also sources of conflict which could draw Iraq's neighbors into the war.

Turkish patience is running out over the cross-border raids by Kurdish militants based in northern Iraq. US Defense Secretary Robert Gates has urged caution, but Ankara is openly debating an incursion to root out the rebels. And it plans to take its case for action to the UN this week.

The signs have become increasingly ominous. For weeks, Turkey has been building up its military presence on its south-eastern border with Iraq in response to cross-border raids by Kurdish rebels. Potentially more concerning, Ankara has been openly considering an incursion into Kurdish-dominated northern Iraq in an attempt to root out members of the Kurdistan Workers Party (PKK) based there.

Turkey, a NATO ally, striving for membership in the EU, battled with Kurdish separatists for decades and worry that an independent Kurdish state on it's border would threaten to provoke a civil war. The PKK was a particular threat.

The main characteristic of PKK attacks was the use of indiscriminate violence, and PKK guerrillas did not hesitate to kill Kurds whom they considered collaborators. Targeted in particular were the government's paid militia, known as village guards, and schoolteachers accused of promoting forced assimilation. The extreme violence of the PKK's methods enabled the government to portray the PKK as a terrorist organization and to justify its own policies, which included the destruction of about 850 border villages and the forced removal of their populations to western Turkey.

Iran and Syria have similar worries.