"Turkish media sources are telling us that the clash took place right on the border," Al Jazeera's Barnaby Phillips in Silopi, Turkey, said.
"We know that the Turkish military has been patrolling more and more agressively, more and more actively along the Iraqi border, and in a sense that means that these kinds of skirmishes and attacks are more likely to take place."
Ankara says the PKK uses bases in the mountainous region across the nearby border to attack Turkish targets.
On Saturday, Recep Tayyip Erdogan, the Turkish prime minister, said his country expected the United States and Iraq to take action against the PKK but would take its own measures if it saw no results.
The United States and Iraq urged Turkey not to carry out any unilateral action, fearing it could destabilse northern Iraq.