Compared with Turkey, which has the second biggest army in NATO – more than 500,000 active forces – the PKK is tiny, with an estimated 1,500 to 2,500 armed insurgents inside Turkey, and 5,000 to 6,000 in the neighboring countries, Iraq, Iran and Syria. They are augmented by a significant number of unarmed local militants, ethnic Kurdish sympathizers who provide logistics, support and recruits. Despite its small numbers, the PKK has managed to deny the government control over hundreds of square miles of territory in southeast Turkey.

For the past two months, Turkish aircraft have been pounding PKK bases in the Qandil mountains of northern Iraq, at times sending bombers up almost every night, according to diplomatic sources. Last week, it moved a squadron of U.S.-supplied F16s to Diyarbakir, in southeastern Turkey, and while this was widely seen as a precautionary move after the exchange of shells with Syria, the base in question is the primary launching pad for attacks against PKK bases in Iraq.

PKK forces dive into their bunkers when the flights take off, thanks to a primitive but effective warning system. According to defectors, the PKK rank-and-file all stay tuned to a Kurdish radio station called Radio Mezopotamya, and when flights take off, listeners phone in coded song requests.

The Turkish military also has deployed specially trained forces as in Beytussebap and high tech equipment such as drones, while the country’s ruling Justice and Development Party has pursued a strategy of economic development with political concessions responsive to Kurdish demands to restore their cultural identity. Prime Minister Recep Tayyip Erdogan has even hinted recently that he might start talks with jailed PKK leader Abdullah Ocalan, who spent the past 14 months in solitary confinement in a Turkish prison. Ocalan’s brother was allowed to visit him and quoted him as condemning the PKK’s offensive as “irresponsible.”

Iraqi Prime Minister Nouri al Maliki, now in a growing public dispute with Turkey over a variety of issues, has demanded that Turkey stop all intervention in northern Iraq’s Kurdistan region, a demand that Turkey has ignored.

On Oct. 4, when the Turkish Parliament gave the government a green light for retaliation against Syria following the killing of the five Turkish civilians, it explicitly approved the use of force abroad, without specifying against which countries.

Three days later, the Turkish military’s general staff announced that it had established 15 zones of operation in Kurdish areas, covering some 611 square miles, where all entry is forbidden until Jan. 7, 2013. At least two of those exclusion zones extend into neighboring countries – Syria and Iraq, according to the coordinates posted on the military’s website.

All are miles from the areas where Syrian shells have been falling inside Turkey.