Blacksnake's Lair; From deep in the hills, Kurdish rebels are stirring up Turkey and Iran, and threatening the one calm part of Iraq.(Murat Karayilan)

Byline: Michael Hastings (With Owen Matthews and Sami Kohen in Istanbul and Michael Hirsh in Washington)

Murat Karayilan prefers to travel in darkness. Under cover of a starry night, the Kurdish guerrilla chief's white Nissan Pathfinder crawls up a narrow gravel road in Iraq's mountainous far north, only the headlights giving his presence away. Karayilan--his last name translates to "blacksnake"--is a hunted man. Across the eastern border, Iran's anti-U.S. leaders would like nothing better than to see him jailed or dead. To the west, America's longtime allies in the Turkish government likewise hate and fear him. The U.S. State Department and the European Union both list his group, the Kurdistan Workers' Party (PKK), as a terrorist organization. "We are not terrorists," says Karayilan, ensconced in a sparsely furnished dwelling with a stone floor. "The U.S. has seen us through the eyes of our enemies. We want you to see us as friends. We are not attacking, we are defending ourselves."

The invasion of Iraq opened a whole Pandora's box of destabilizing forces--among them, a surge of nationalism among the estimated 36 million Kurds who hail from the land that stretches from Turkey and Syria in the west, to Iraq and Armenia in the east. The PKK, which fought Turkey in a vicious war that cost 37,000 lives from 1987 to 1999, abandoned its truce two years ago, after the fall of Saddam Hussein. The rebels still see themselves as standing up against centuries of often brutal repression. This year the Kurdish group has staged more than 250 attacks on Turkish security forces, in one bloody week killing 14 Turkish soldiers, a toll unmatched since the worst of the fighting in the '90s. In recent weeks the violence has escalated, as everyone tries to inflict as much damage as possible before winter snows interrupt the war. Last week Turkey shelled three Iraqi villages near the border town of Zaho, according to the government of Iraqi Kurdistan. Iran's artillery was busy as well, killing a villager near the town of Hakurk. For its part, the PKK and its allies have been blamed for at least eight bombings across Turkey and for the kidnapping of a local official's son.

U.S. and Iraqi officials worry that the fighting will spin out of control. Ankara threatens to launch cross-border raids to get rid of the rebels, and the guerrillas themselves say Iranian jets and ground forces have crossed the border more than once this year. Even as U.S. forces struggle to contain the chaos and violence everywhere else in Iraq, the danger now is that the fires could spread to the Kurdish north and beyond. No one was very impressed by the PKK's declaration of a unilateral ceasefire over the weekend. At least four previous ceasefires have failed, and last week Turkey issued a pre-emptive dismissal of any PKK peace offer. "The PKK usually hibernate over the winter," says one Turkish diplomat. "When spring comes, they are up to their usual business again." Everyone knows the hunger for Kurdish rights is not going away.

The PKK is the only authority in its corner of Iraqi Kurdistan. To get there you climb a winding road where even the shepherds carry AK-47s, into the Qandil Mountains, a stretch of high peaks straddling the borderlands of Iraq, Turkey and Iran. The last Iraqi government checkpoint is at the foot of the mountains, guarded by soldiers from Iraq's Kurdish Regional Government. It flies the flag of Iraqi Kurdistan, a yellow sunburst on a field of green, white and red. The flag at the next checkpoint, almost two miles above sea level, belongs to the PKK: a red star on yellow sun outlined in green. Armed guerrillas make sure no one goes farther without official permission from their central command. Around the bend, an immense portrait has been painted on the rocky hillside--the face of the PKK's founder, Abdullah Ocalan.

Ocalan--Apo, his followers call him--launched the PKK in 1978 as a Marxist organization opposing Turkish rule. By the 1980s, the ...