DIYARBAKIR, Turkey — Nasir Dogru says his son must have been important. He has often seen the 18-year-old on local Kurdish television channels, his smiling face flashing across the screen.

Perhaps he was a commander, he says. Neighbors and friends say so too. They call the teenager, Ferhat Dogru, a martyr.

“He was very brave,” says Nasir. “He was the first martyr of the Sur struggle.”

About 16 months ago, young Ferhat left his home in Diyarbakir’s Baglar neighborhood, a rough district racked by poverty. His family believes he stole off into the mountains of northern Iraq, joining the Kurdistan Workers Party, or PKK, which has been waging an insurgency against the Turkish government for three decades.

Ferhat returned home after eight months. Combat pitting Turkish security forces against Kurdish fighters was escalating throughout Turkey’s restive and predominantly Kurdish southeast.

A sniper shot him dead four months later, last November. Ferhat had been battling as part of the militarized ranks of the PKK’s youth wing in Diyarbakir’s Sur district.

In its early years, the PKK sought an independent state for the Kurds, an ethnic minority largely spread over portions of Turkey, Iran and Iraq. It later softened its goals to demanding improved rights within Turkey for the long-repressed group.

Both Turkey and the U.S. describe it as a terrorist organization.

As Kurdish militants strike at urban centers across Turkey, a new generation of more radical youth has emerged. Products of the vicious security crackdowns of the 1990s, they increasingly appear to operate outside the PKK’s top-down hierarchal structure, analysts say.

Since the collapse of a three-year peace process in July, Turkey’s southeast has spiraled into war, with youth militants forming the vanguard. Two recent car bomb attacks in Ankara, the capital, and a mortar attack on an Istanbul airport in December have raised fears that the violence is spreading well beyond the country’s Kurdish heartland.

“The shift to urban combat … likely undermined the PKK’s capacity to control militants,” says Howard Eissenstat, a Turkey expert at St. Lawrence University in New York. “The model of highly indoctrinated, disciplined troops that the PKK used in the mountains does not really apply to the cell-based urban units who are at the forefront of the conflict right now.”

It is possible, says Eissenstat, that the PPK “is now leading from behind and no longer capable of controlling its cadres.”

On March 13, a suicide car bomb brought carnage to the Turkish capital, killing 37 people at a busy transport hub and park in the city’s central Kizilay neighborhood. Ankara says a 24-year-old female PKK militant carried out the attack, which raised widespread fears of a dramatic shift in insurgent tactics.

An intransigent PKK offshoot, the Kurdistan Freedom Falcons, claimed responsibility for the attack in a statement published on its website Thursday. It was the organization’s second attack in Ankara in less than a month.

Kurdish fighters have traditionally been wary of exacting a high civilian toll, as they seek domestic and international legitimacy.

“Assuming that the … attacks in Ankara are in fact related to the Kurdish issue, they mark a remarkable escalation of the level of violence,” Eissenstat says. “The use of car bombs to ensure a large number of casualties and the explicit targeting of civilians are not something we typically associate with the conflict in Turkey.”

The rise of a PKK-linked Kurdish faction in Syria — with which Turkish-backed militants have repeatedly clashed — and its ability to hold territory and establish self-governance, analysts say, has probably encouraged youth and splinter factions to adopt a more radical stance than the group’s leadership.

This appears to be empowering PKK hard-liners at the expense of the somewhat more conciliatory figures within the group, such as the leader of the insurgents’ armed wing, Murat Karaliyan.

Ferhat was an example of the newly radicalized youth. According to his father, he became fascinated with the PKK during his early teenage years. He had never been very interested in school, preferring to kick around a ball.

“He loved the [Kurdistan Workers] Party so much,” says Nasir.

His family says he was angered by what he believed was the oppression of the Kurdish people. He dropped out of school at 14.

“He was a funny child, our youngest,” says Nasir, a 55-year-old retired civil servant, sipping a glass of tea. “When he was born, he balanced our family: four boys and four girls.”

The Dogru home is a sparse, humble place. Worn furniture points toward an old television set, a local Kurdish station broadcasting an interview with PKK partisans dressed in baggy green fatigues.

Ferhat’s mother, Hamdiye, says that “he never stole or treated people unfairly.” But his admiration for the PKK was obvious to all.

“He was not a bad boy. He was very positive,” says Hamdiye. “But he knew that we were struggling against oppression. He wanted to protect us.”

Ferhat returned home from the mountains as violence in Turkey’s southeast began to spiral out of control midway through last year.

“We don’t know exactly what he had been doing there,” his father says.

In areas of Turkey, young militants dug trenches and battled security forces in increasingly bloody street-level conflict. Ankara imposed strict curfews — bolstered by tanks and attack helicopters — on embattled towns and cities throughout the southeast, vowing to crush “terrorism.”

“The collapse of the peace process has destabilized Turkey writ large — and only one aspect is the need for sustained counter-terror operation,” says Aaron Stein, a senior fellow at the Atlantic Council. “The military will, without question, be able to clear cities.”

But, he adds, most Turkish security officials expect the PKK to mount a spring offensive.

The Dogrus say that they have seen enough violence in the southeast.

Nasir lifts a length of fabric in the colors of the Kurdish flag, revealing a photograph of a smiling Ferhat wearing a bandanna.

On Nov. 6, he was shot in the stomach as clashes raged near Diyarbakir’s four-legged minaret, a hot spot in the recent violence. Turkish authorities allowed the transport of the wounded youth to a hospital, where he died.

“I am proud of him,” says Nasir. “He is among the martyrs in the cemetery.”