By Sarah Rainsford
BBC News, Istanbul
Heavy snow on the Iraqi border has hampered the Turkish operation
In a remote, snow-covered region of northern Iraq, Turkish troops have been battling Kurdish PKK rebels for five days.
Their mission is codenamed Operation Sun, after the three-year-old daughter of a Turkish soldier killed last year in a PKK ambush.
A photograph published on the chief of staff's website shows a soldier scratching a defiant message onto the side of a missile: "Martyrs never die."
The mood here is one of revenge - and there is a desire to stop the PKK launching further attacks on Turkish troops and civilians from northern Iraq.
Ankara argues as many as 3,000 PKK members use the region as a safe haven.
Others are based in south-eastern Turkey, where they have been fighting for more autonomy and rights for Kurds for more than two decades.
By Tuesday evening the military website recorded 153 PKK militants killed in Iraq and 19 Turkish troops. The statement said heavy snow had hampered progress since Monday.
Pro-PKK websites claim dozens of Turkish soldiers have been killed.
"Of course Turkey does not expect to finish off the PKK 100%," says Serhat Erkmen, of the Asam think tank in Ankara.
He argues the military had to mount a show of strength after a wave of devastating ambushes by the PKK on Turkish troops in September and October last year.
"I think the strategic aim of this operation is to demolish the main PKK bases in northern Iraq and prevent new attacks from there in spring. Turkey wants to clear the area as far as possible," Serhat Erkmen says.
The campaign began with air strikes in December, supported by real-time intelligence from the United States. Deploying ground troops was a crucial follow-up.
So far, it is widely viewed here as a success.
Daily statements from the Turkish military report that dozens of PKK hideouts and weapons stores have been shelled and destroyed.
Local media claim key PKK camps have been cleared along the Iraq border and in the foothills of the Kandil mountain.
The region is so inaccessible that it is impossible to verify any information independently.
But the longer the troops stay in Iraq, and the further south they venture, the more uncomfortable Baghdad becomes.
On Tuesday, the government there denounced the incursion as a violation of Iraq's sovereignty and called on the Turkish military to withdraw immediately.
"We will continue until the job is done. We are determined," Turkish foreign ministry spokesman Levent Bilman told the BBC.
"We have no designs on Iraqi territory; we only engage the terrorist organisation. Once our military and intelligence tells us there is no more threat, our troops will come out as promised," Mr Bilman said.
Most analysts here believe that means Operation Sun will continue for another week at least. Some say considerably longer.
"There are hundreds of terrorists attacking Turkey from Iraq, and the Iraqi government condemns us?" wonders Sedat Laciner, who heads the International Strategic Research Organisation in Ankara.
About 3,000 PKK rebels are thought to be based in Iraq
He points out that for many years, Iraq has been unable to rein in the PKK itself.
"They should understand our problem. The PKK is killing our people. Turkey could not allow that to continue."
Until now, international reaction to the cross-border operation has been remarkably muted.
Washington described the PKK as a "common enemy", and only urged Ankara to keep its incursion short and closely focused.
The positions of the UN and EU have been similar, suggesting a degree of sympathy with Turkey's cause. Ankara is anxious to maintain that.
So with no obvious sign that the military operation is ending, the politicians appear to be gearing up for their own, diplomatic offensive.
On Tuesday, the foreign minister confirmed an envoy would be sent to Baghdad very soon, but gave no details.
"It's crucial to keep the international community on side with this. The government must explain our position," Mr Laciner believes.
Prime Minister Erdogan says the PKK threatens Turkey's integrity
Like many analysts, he also argues that the government must also press ahead with reforms aimed at improving the situation of Turkey's Kurds.
That would make it harder for the PKK to attract new recruits and help sustain international support.
"We need to fight terrorism, as well as the terrorists," Mr Laciner says. "To address the social and political dimensions of the Kurdish problem here at home - not just the military dimension."
For now though, newspapers and the airwaves are filled with the latest twists and turns in the military drama.
They are interspersed with images from the funerals of soldiers killed in action, and huge crowds shouting furious slogans against the PKK.
Despite the loss of life, there seems to be little appetite here yet for the military to end its incursion.
"I believe all the troops will withdraw eventually, they won't set up any buffer zone," says Serhat Erkmen.
"But I think this ground incursion is just the first. In future, when the military judges it necessary - they will go into northern Iraq again."