ISTANBUL -- Turkish tanks are deployed on hilltops overlooking Syria and additional combat aircraft have been moved to bases close to that war-torn country in an escalation that began Oct. 3, when a Syrian artillery round landed in the border town of Akcakale, killing five Turkish civilians.

But while the developments have all the appearance of two countries heading for a major clash, the Turkish government’s moves may relate not so much to the civil war now raging across Syria, but to what is for Turkey a far deadlier conflict: The long-running war against militant Kurdish separatists, whom the Turkish government sees as a threat to the existence of the state itself.

Since July, when the outlawed Kurdistan Workers’ Party, or PKK by its Kurdish initials, launched its latest offensive, at least 112 Turks have died, 99 of them from the army and other security forces and 13 civilians, according to a McClatchy compilation of Turkish news accounts. Government forces claim to have killed 325 separatists, and casualties mount.

One of the most serious assaults occurred early last month, when some 70 PKK guerrillas stormed the center of Beytussebap in southeastern Sirnak province, blew up the town’s only bridge and opened rifle and rocket fire from four different directions on the governor’s office, a military barracks and police offices. They killed 10 security personnel. The army deployed a special commando unit and claims to have killed 50 of the attackers. Continuing incidents have rattled the country.

Turkey also sees a growing PKK threat immediately across the border.

In apparent retaliation for Turkey’s backing of the rebellion against Syrian President Bashar Assad, Syria has transferred control of many Kurdish towns in northern Syria to the Syrian affiliate of the PKK, causing alarm in Ankara. Moreover, the PKK is said to have deployed a sizable number of fighters – possibly 2,000 or more – into Kurdish Syria to bolster its local affiliate there, the Democratic Union Party.

Turkey, the United States and the European Union all view the PKK as a terror organization whose aim is to break up the Turkish state. Turkish leaders say they will not permit a PKK-led entity to be set up on its border.

In the view of many diplomatic observers here, if Turkey does use force in or around Syria, it will not be seeking the overthrow of Assad, which is not a core security concern for Turkey, but the demise of the PKK, whose hope to set up an independent Kurdish state would impinge on the sovereignty of Turkey, Iran, Syria and Iraq.

The war against the PKK, which began in 1984 and has claimed as many as 40,000 lives, became a good deal more complex as a result of the Arab Spring. Assad not only has refused to curb PKK activities within his borders, but there are signs he has actively encouraged the PKK’s latest offensive.

A defector, who broke with the PKK in late June, told Turkish officials that “large amounts of money” flowed from Syria into PKK coffers in the first half of 2012, according to documents that McClatchy was allowed to read.

Additionally, Turkish officials now believe the commander of the current PKK assaults in Turkey is Fehman Huseyn, who’s also known as Bahoz Erdal, a Syrian Kurd who is based in northern Iraq.

Meanwhile, Syria’s close ally, Iran, has done nothing to discourage the use of its territory by PKK guerrillas.