Turkish forces said today they had repelled an attack by Kurdish militants near the Iraqi border.
President Abdullah Gul has warned the rebels that Turkey's patience was running out.
Ankara has massed as many as 100,000 troops along the mountainous border ahead of a possible cross-border operation against around 3,000 rebels of the Kurdistan Workers Party (PKK), who use northern Iraq as a base for attacks on Turkey.
Turkish security sources have confirmed a series of sorties by warplanes and ground troops since Sunday into Iraqi territory, though Ankara has said it still hopes diplomacy can stave off the need for a full-blown ground invasion.
Around 3,000 Kurdistan Workers Party (PKK) have used the 3,000 rebels of the Kurdistan Workers Party (PKK) who use northern Iraq to launch attacks on Turkey.
Iraqi, Turkish and US diplomats have stepped up efforts to avert a Turkish incursion but Mr Gul said Turkey would not tolerate more PKK attacks from Iraq.
"Although we respect the territorial integrity and unity of Iraq, Turkey is running out of patience and will not tolerate the use of Iraqi soil for the purpose of terrorist activities."
The United States is keen to avert major Turkish military action in northern Iraq, fearing it would destabilise not only the most peaceful part of that country but potentially the wider region.
"[The United States] may not want us to carry out a cross-border operation. But it is we who will decide whether to do one or not," Turkish Prime Minister Tayyip Erdogan said.
Public pressure on the Turkish authorities to act has grown since rebels killed 12 soldiers last weekend. The PKK - considered a terrorist organisation by the United States, Turkey and the European Union - said they it had captured eight soldiers.