As violent instability convulses much of Iraq, the country's neighbors are keeping a watchful eye.  In recent weeks, Turkey has warned Kurds in northern Iraq not to make any moves to declare themselves independent from Baghdad.  Turkey has a large Kurdish population of its own, and the government in Ankara is worried by the violence in Iraq, fearing that it threatens the country's territorial integrity.  Correspondent Simon Marks traveled to the Turkish border with Iraq, and sends this report.

You see the trucks long before you see Turkey's border with Iraq.  For several miles they line the roadside, loaded with steel, cement and food.

It can take several days to secure permission to cross into Iraqi territory.  Yet every day 4,000 truckloads of Turkish goods cross the border into northern Iraq and Iraqi oil crosses the border going out.

Many of these drivers are Turkish Kurds from the southeast of the country, and they have a unique opportunity to see life on both sides of the border.  Some of them, like driver Ethem Ozer, believe that a single independent Kurdish state would better support Kurdish families in both Turkey and Iraq.

"We want to unite,? he says. ?Why do we want to unite?  There shouldn't be any problems between us.  If there is no business here, maybe they have some business, so we go and work there.  And if there's no work there, they could come and work here.  We have rights, and so do they, and that's why we want to unite."

But that kind of talk terrifies Turkey's government.  It vigorously opposes the idea of a Kurdish state based on Turkish or Iraqi territory.  Rebels trying to achieve that goal are now based in the mountains of northern Iraq.  The Turkish government says fighters with the outlawed Kurdistan Workers' Party -- the PKK ? are being given safe haven in U.S.-occupied Iraq, even though the U.S. government brands the PKK a terrorist organization.

Abdullah Gul is Turkey's Foreign Minister.  He says, "We can't understand this, you see.  If an enemy regime gives this opportunity to them, we understand this, you see.  That is an enemy regime, you see.  But this is a friendly country.  The country we are helping.  The country that is controlled by our allies, and we are helping them.  This is the problem, you see?"

The U.S. government says it is taking action against the PKK, in partnership with the Turkish government.   But the U.S. Ambassador to Turkey, Ross Wilson, concedes there are other problems in Iraq that are taking precedence.

"U.S. forces are rather busy.  They face a number of terrorist problems, a number of insurgent problems,? the ambassador says.  ?They have focused their primary energies on those insurgent issues that directly challenge the center of gravity in Baghdad and that challenge our forces.? 

In the ancient backstreets of Diyarbakir, the largest Kurdish city in southeastern Turkey, the PKK does not appear to be winning the battle for hearts and minds. This city was originally settled more than 5,000 years ago.

Today it is home to Kurds who are struggling to make a living, a fact that carpenter Sherif Uraki believes the PKK doesn't fully understand.  "What the PKK is doing, or what the government is doing is not important to us.  We are just trying to earn enough money to buy bread,? he says. ?And from the early hours of the morning we are working here. We are just trying to take bread to our homes, and I don't think either the PKK or the government has any idea of the conditions under which we are living.  We're just trying to survive."

Ongoing instability could lead the Turkish army to take up positions on Iraqi territory in a bid to overcome the PKK.

Retired General Edit Baser is the Turkish government's special representative on counterterrorism.  "You cannot just sit and watch when your neighbor's house is on fire, OK?  You got to do something about it,? he explains.  ?Because that fire may come into your house, your yard.  So you have to take some measures to avoid it, and to help your neighbor if you can.?

The general and many politicians back in Ankara fear Kurdish ambitions for a separate state making up northern Iraq and Kurdish areas in Turkey. They have already fought a 20-year war against the PKK and seem ready to fight another if necessary. The Kurds are caught in the middle and they wonder whether events will bring them stability and opportunity, or yet more uncertainty and distress.