BAKSAN, Russia » On Friday, a week before the Olympics were set to open just 180 miles away, Russia’s security forces appeared on Makhov Street at 8:30 a.m. and cordoned off the area around a brick and stone house. One of the men inside called his father, who said it was the first he had heard from his son in 10 months.

"He said, ‘Papa, we’re surrounded,’" the father said. "’I know they’re going to kill us.’ Then he said farewell."

The Russians and the men inside exchanged gunfire, pausing only to allow a woman and two children to leave the house. By the time the shooting ended in the afternoon, four men inside were dead, according to official accounts. The Russians then blew up the house, leaving a bloodied pile of rubble and a crowd of sullen, angry neighbors.

For the first time in history, the Olympics are being held on the edge of a war zone. The conflict is one of the longest running in the world, a simmering, murky battle between increasingly radicalized militants who operate in the shadows of society and a security force that can be brutal, even when lethally effective.

The symbolic importance of the games for Russia and for President Vladimir V. Putin has turned Sochi itself into a tantalizing target for Islamic terrorists who have vowed a wave of attacks to advance their goal of establishing an independent caliphate across the North Caucasus.

The threat has prompted the Kremlin to mount what officials and experts have described as the most extensive security operations in the history of sporting events, sealing off the city and conducting months of operations like the one here to crush militant cells across a region that stretches from Dagestan on the Caspian Sea to Sochi on the Black Sea, using tactics that critics say only fuel more violence.

"It’s terrifying what’s happening now: the total destruction of our youth," the father said, agreeing to speak only if not identified because he feared reprisal. "Everyone is scared. Everyone is running away. Some go to Moscow. Some further away. People start to protect themselves after things like this."

The Olympics have focused new attention on this country’s most-wanted terrorist, Doku Umarov, and threats of fanatical attacks like the ones in Volgograd that killed 34 people in December when suicide bombers struck mass transit. But the war in Russia more often takes the shape of events in places like Baksan. Rustam Matsev, a lawyer in the republic, Kabardino-Balkaria, called it "a slow-motion civil war."

Even if Russia succeeds in keeping Sochi safe, the violence is certain to grind on here in the Caucasus when international attention moves on, nurtured by the nihilistic ideology of the international jihad and punctuated by terrorist attacks outside the region that experts say Russia, like other countries, will never be able to prevent completely.

"You don’t need much to do this," said Ekaterina Sokirianskaia, the North Caucasus project director for the International Crisis Group. "You need a committed jihadi and a bomb, which is quite cheap and you can make it at home. It’s difficult to deal with."

In 2013, violence between militants and security forces left 529 people dead in the North Caucasus, according to a list compiled by the news site Caucasian Knot that does not include the attacks in Volgograd, a city farther north. Of those killed, 127 were Russian security officers, a death toll on a scale of the 160 soldiers who died during the same period in NATO’s war in Afghanistan.

The level of violence has dropped significantly since tens of thousands died during Russia’s two wars against separatists in Chechnya, who once hoped the collapse of the Soviet Union in 1991 would clear the way for the republic’s independence. The second war, under Putin’s leadership, lasted 10 years, but it crushed the rebels and drove the Chechen rebel commanders underground or "into the forest."

There, they gradually turned the cause of Chechnya’s independence into a broader, more radical vision of holy war that has little popular support but has nonetheless attracted adherents across the region.

Chechnya is no longer even the deadliest republic in the region, according to Caucasian Knot, having been surpassed in deaths and injuries last year by some of its neighbors, notably Dagestan, now the most dangerous region in Russia, Ingushetia and Kabardino-Balkaria.

Umarov, who is described as Russia’s Osama bin Laden, has led the insurgency since 2006, but his influence and operational command are now a matter of dispute. Many officials and experts describe him as little more than a figurehead for a diffuse constellation of terrorist cells operating independently. Some think he might even be dead.

"For an insurgent, he’s quite an old guy," Sokirianskaia said. "He’s nearly 50. He’s had many injuries. I can’t rule out that he’s dead."

The terrorist cells are now so small and so deeply underground that they appear unable to undertake the sort of large-scale operations that seared Russia early in Putin’s rule, including the siege of a theater in Moscow in 2002 and a school in Beslan in 2004, both of which involved dozens of fighters.

"There is no real organization there," said Mark Galeotti, an expert on Russia’s security forces from New York University who is now conducting research in Moscow. "There are people who are networked together."

He expressed doubt that Umarov would have known in advance of the bombings in Volgograd, for example, even though a previously unknown cell from Dagestan claimed responsibility for it last month saying that it was carrying out his threat last summer to attack the Games.

As the attacks in Volgograd showed, the insurgents can still carry out spectacular and deadly suicide attacks against "soft" targets like trains, stations and buses, if not at will, then at least with appalling regularity. While attacks in the Caucasus often target Russian security operations, those outside appear intended to maximize terror by striking at civilians. That kind of attack, rather than one in Sochi itself, experts say, is more likely during the Olympics.

While suicide bombings have been a recurring tactic since the second Chechen war — giving life to the lurid mythology of the "black widows," women avenging the deaths of husbands, fathers, brothers or sons — the motive has shifted, according to Sokirianskaia. Those women now, she said, are driven less by a clear political goal than by the pursuit of martyrdom and heavenly reward.

Paradoxically, the most radicalized vision of an Islamic insurgency has little appeal among the majority of people in the region. There is no cult of martyrdom here except online. While the region is overwhelmingly Muslim, few appear to support either the goal of separatism or the imposition of an explicitly Islamic form of government.

The actions of the Russian security officers, however, fuel resentment, as do ethnic tensions and impoverishment. In Kabardino-Balkaria’s capital, Nalchik, a sense of disenfranchisement resulted in an uprising against security forces in 2005 that resulted in 135 deaths.

"People do not support them actively, but they do not resist," Murat Khokonov, a professor of physics at Kabardino-Balkaria State University, said of the insurgent networks. "They don’t trust the security structures. They don’t trust the police."

The insurgency has been driven so far underground that the reverberations in society are usually felt only when militants battle police. On the night of Jan. 11, in a small village near Baksan, Khizir Tlyepshev told his wife he was leaving for the public bathhouse shortly before Russia’s security forces cordoned off the area, searching for four men who had sprayed a police car with bullets. When officers came to their house, they demanded to know the location of a bunker.

"What bunker?" his wife, Ramyeta, said she told them.

Ten days later, officers in masks came a second time.

Inside a chicken coop behind the house, where the Tlyepshevs’ four children often played, the officers uncovered a shallow trench, and there, the authorities said, they found four containers with more than 100 pounds of explosives. Ramyeta Tlyepsheva said she had no idea the trench was there, how the explosives were put there or whether her husband could have been involved.

Khizir Tlyepshev has not returned or contacted his wife since that night. His wife does not know whether he is in custody or in hiding, an accomplice of Russia’s insurgency or a victim of its security forces. She does not know if he is alive.

"I feel like I’m trapped between them," Ramyeta Tlyepsheva said.

On the eve of Sochi, even the Olympics, portrayed by officials and state media as a unifying celebration of the country’s re-emergence on the world stage, are regarded with ambivalence here. The monumental relay of the Olympic flame, a staged event that went as far as the North Pole and the International Space Station, was sharply curtailed in the Caucasus, held inside well-guarded stadiums, including those in Dagestan, Chechnya and, last week, in Nalchik.

Many of the ethnic groups in the Caucasus are related to the Circassians, who consider Sochi part of their homeland, conquered by the Russians in the 19th century after what activists today hope to publicize as an act of genocide.

Valery Khatashukov, the chairman of the Human Rights Center in Nalchik, said that Russia stirred resentment by continuing to treat the region as a colony to be conquered. Instead of holding elections, Putin’s Kremlin simply appoints leaders, leaving the people disenfranchised.

Matsev, the lawyer, echoed the ambivalence of the plight that ensnared Tlyepsheva’s husband. She did not oppose the police. Nor did she support the insurgency.

"It’s like an unhappy marriage where there can be no divorce," he said "There is too much in common to divorce — the ties are too close — but too much has happened to be happy together."

© 2014 The New York Times Company