At a checkpoint outside the northern Iraq town of Makhmur, I saw something I'd never seen before in Iraq.
Two men were checking cars. One was young and wearing a sand-colored uniform of the official Iraqi Kurdish forces, called the peshmerga. The other was older, grizzled and dressed in an olive-green, traditional Kurdish overall, and he's with Turkey's Kurdistan Workers' Party (PKK).
"We're happy to be working together," said the older man, Hajji Hussein Abdulrahman.
This is a new development. Until recently, Iraqi Kurdish authorities and the peshmerga didn't deal much with the PKK. There's a long rivalry between the two. Plus, Turkey and the U.S. consider the PKK to be terrorists based on their attacks against civilian targets in Turkey for many years.
But some of those attitudes began to change when the self-described Islamic State, also known as ISIS, charged into northern Iraq and overran large chunks of territory, including this town in June.
The peshmerga were struggling to fight back. But thousands of PKK supporters, who had been kicked out of Turkey, were living in a nearby refugee camp. They picked up their old rifles and joined the fray.
"We evacuated all the civilians, the women and kids and elderly people from the camp," said Polat Mohammad Khalil, a civilian official at the camp. "And then we reorganized ourselves as guerrillas to confront ISIS."
With the help of U.S. airstrikes, the combined Kurdish forces pushed out the Islamic State extremists.
"It was the first time for us to coordinate with the peshmerga — to be in one place, one position," Khalil said. "So we have to thank ISIS because they unified us."
The president of Iraq's semi-autonomus Kurdish region, Masoud Barzani, has long had bad relations with the PKK. But he came to thank them. And many other people in the town of Makhmur also seem grateful.
Aram Karim, who was making sandwiches in a shop, said the PKK help was a surprise. The Kurdish camp has been here since the 1990s, but the Turkish Kurds never did any fighting.
"They were always good neighbors," he said, "but I like them much more now."
This isn't the only place were Kurdish fighters have been active. On northern Iraq's Mount Sinjar in August, the PKK helped tens of thousands of minority Yazidis escape the advancing Islamic State.
And the Syrian Kurdish militia, known as the YPG, has been battling to keep the Islamic State out of the town of Kobani.
In the main Iraqi Kurdish city, Irbil, Shiman Eminoglu is a politician from the BDP party, which leans strongly toward the PKK. She says the PKK is fighting for everyone's benefit, and that this should be recognized by the United States.
"I feel there is a very big injustice against the PKK because they put them on a terror list and they classified them as a terror organization," Eminoglu said. "I think the whole international community should change its opinion about the PKK."
Many think that's unlikely. Turkey blames the PKK for the deaths of three soldiers just this week and has been targeting them with airstrikes.
"The United States will not, on the PKK, change policy," says Turkey expert Henri Barkey of Lehigh University. "It doesn't talk to the PKK, it considers it a terrorist organization, it follows the Turkish line."
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