By Crispin Thorold
BBC News, northern Iraq
The Kandil mountain range runs across northern Iraq, but it is in the area where the borders of Turkey, Iran and Iraq meet that many of the rebels from the PKK are believed to be hiding.
The PKK have been based in the Kandil mountains for some 20 years
The Turkish government says that the 3,000 Kurdish fighters based there use the region to launch attacks inside Turkey.
On a hilltop close to the town of Ranya, there is a spectacular view of the jagged peaks of the Kandil mountains. On one side you look towards Turkey and on the other Iran.
Fighters from the PKK - or Kurdistan Workers Party - have been based in these mountains since the early 1980s and repeated attempts by the Turkish military to drive them out have failed.
Now the government in Ankara has called on the Kurdish authorities in northern Iraq to act against the PKK.
The Iraqi President, Jalal Talabani, and the president of the regional government in northern Iraq, Massoud Barzani - both of them Kurds - have said that they are not able to remove the PKK.
In Ranya, local people have got used to their neighbours in the PKK.
The PKK are popular in Ranya
"I like the PKK. They are very good people," one man said.
"They look after people here. The PKK are fighters but they are not dangerous people like other people, like Islamic people. Like Osama bin Laden," he added.
The recent shelling by the Turkish military in northern Iraq took place some distance from Ranya and residents in the town did not seem worried about the prospect of a Turkish military invasion.
However, they did question the motives behind the army's plans.
"The Turkish government wants to attack all the Kurdish people and not just the PKK," said one middle-aged man.
"Turkey just wants to make things complicated here in the Kurdish region of Iraq," he said.
That view is shared by many local politicians who question why the Turkish military and government are making such hostile statements now, about a problem that they have not solved in the past.
There have been dozens of Turkish incursions into northern Iraq since the PKK began its war in 1984.
The Kurds argue that that they have failed. After all, they say, the PKK are still in the Kandil mountains.
Ankara has demanded that the Kurdish regional government do more to tackle the PKK.
As in all areas of northern Iraq there are frequent checkpoints outside Ranya. They are manned by members of the Iraqi army - and around here, they are all Kurds.
One army major told the BBC that he had not been given any orders to act against the PKK. The supply lines to the organisation still appear to be open.
If that is the case the PKK can continue to operate and in this area they will have the sympathy of the local people.
In Ranya an elderly man in the market caught the mood of the town.
"The PKK are human beings like us," he said. "They just want to stay in their country.
"The Turkish government is like Saddam Hussein's regime. In the south of Turkey they cannot even study their own language. The situation is getting worse. We just want it to improve and for there to be peace," he added.