Hitting Kurdish rebels in northern Iraq carries political risks for Turkey.
The mobilizing military forces have yet to begin the large-scale incursion into northern Iraq to hunt Kurdish guerrillas that Turkey is threatening.
But reports of limited "hot pursuit" across the border Wednesday illustrate the knife-edge tension in the wake of a string of lethal attacks in Turkey blamed on Kurdistan Workers' Party (PKK) separatists based in northern Iraq.
Analysts say news of the raid is a warning to both the US and Iraqi Kurds, nominally in control in northern Iraq, to clamp down on the PKK, which has waged a fight for a homeland in southeast Turkey since 1984.
The latest violence comes in the run-up to elections next month and are causing Turkey's Islamic-leaning ruling party and the secular military, often at odds, to weigh popular will for an attack against strategic drawbacks.
"We are not there to penalize the people of Iraq," says Seyfi Tashan, director of the Turkish Foreign Policy Institute at Bilkent University in Ankara, the capital. "But we can't tolerate the PKK receiving assistance to kill Turks." On Wednesday, the military announced a "temporary security zone" across three provinces near the Iraqi border where they will limit land and air travel until Sept. 9.
Chief of Staff Gen. Yasar Buyukanit has said that "political" decisions are needed before expanding to "targets" beyond the PKK and going after Iraqi Kurds led by Massoud Barzani, a US ally, whom Ankara accuses of harboring rebels.
"A parliamentary decision is required," Prime Minister Recep Tayyip Erdogan told Kanal 24 television late on Wednesday. "If we are to take a cross-border step, we'll negotiate this with our security forces, and when such a thing is necessary, we'll take it to parliament."
Turkey recognizes "it would be a high-cost exercise for little concrete result," says a senior Western diplomat in Ankara. "They found good reasons not to do this the last 4-1/2 years. [But] if violence gets very bad, then the cost-benefit analysis will begin to change."