ANTAKYA, Turkey -- People here call it Tuscany with minarets.
Turkey's southeastern quadrant, along the Syrian border, is one of its most picturesque, where olive groves dot the rolling farmland and the mountains are sluiced by Evian-clear streams. In the mornings, old women come down the hills to pluck apricots from the market. In the evenings, tourists stroll along the cobblestone promenades, happily searching for a simit, a bagel-like roll, or a scoop of lemon ice cream.
But recently there has been a surge of new arrivals: Syrians, especially battle-hardened Syrian fighters. It is not unusual to see rebel soldiers limping around the holiday town of Antakya on crutches, and countless apartments across this area have been turned into makeshift combat field clinics, crammed with young, burly men nursing gunshot wounds.
Turkish security services insist that they are closely patrolling the 550-mile border. But medical supplies, matériel and fighters slide across the frontier every night, making this charming, quaint part of Turkey the most important base for the growing Syrian rebellion.
"The Turkish police are watching the border, but with their eyes closed," said Ahmed al-Debisi, a Syrian pharmacist and opposition member based in Antakya, who is trying to clandestinely make gas masks out of Coke cans and cotton balls, in case the government of Syria's president, Bashar al-Assad, unleashes chemical weapons.
Syria's intensifying civil war is turning into a raging national security headache for Turkey. Beyond the strain of hosting more than 40,000 refugees -- which Turkish officials said was initially manageable but is now "creating problems" -- a Syrian border post just fell into the hands of a group linked to Al Qaeda, and about a dozen Libyan fighters with bushy beards and black backpacks were recently spotted hanging around Antakya's main hospital, waiting for their wounded "brothers."
It seems the Antakya area is becoming a magnet for foreign jihadis, who are flocking into Turkey to fight a holy war in Syria. One Turkish truck driver said he passed through the Bab al-Hawa border post on Wednesday night and spotted four foreign fighters with guns and rough Arabic accents, leading him to believe they were Pakistani, Afghan or possibly Chechen.
Another border zone, just inside Syria, was seized by Kurdish militias, leaving the Turks deeply concerned that the rapid unraveling of the Assad government could reinvigorate Kurdish militants in Turkey.
When asked a few days ago whether Turkey would strike inside Syria if Kurdish militants used Syria as a base, Turkey's prime minister, Recep Tayyip Erdogan, said: "That's not even a matter of discussion; it is a given."
Turkey is eager to be a global player. Its economy is booming, evinced by the endless new apartment blocks with shiny satellite dishes rising from the cornfields here. The Turks have even recently ventured into bullet-pocked Somalia, where they are trying to establish a beachhead for Turkish influence and business across Africa.
But the conflict next door offers no easy answers. Originally, the Turkish government tried to play nice with Mr. Assad, asking him to reform. When he refused, Turkey threw open the doors to the Free Syrian Army, the dogged but inchoate rebel group, whose nominal leaders operate from a heavily guarded tented camp inside Turkey near the border. The Turks have been delicately trying to steer events in Syria, pushing the opposition to unite, hosting several high-level meetings with Syrian rebel leaders and helping the rebels get weapons, but they are fearful of being dragged in deeper.
"The Turkish people don't want an intervention," said Ilter Turan, an international relations professor at Bilgi University in Istanbul. "This society is enjoying the fruits of economic prosperity, and they don't want it destroyed by some external engagement."
In Antakya, the grumbling is growing louder -- on both sides. This is a tourist town, known for its ruins, its old churches and a museum housing one of the finest collections of Roman and Byzantine mosaics anywhere in the world. The farmland around here is spectacularly fertile, producing cherries, olives, huge sweet melons and a cuisine renowned in food-obsessed Turkey for being especially innovative and fresh.
Abdulmecit Ercin, an insurance broker and Antakya native, remembers all the tourist buses that used to wend their way along the Asi River beneath his office window.
But since the conflict began in Syria, and the border was partially closed, the buses have largely disappeared.
"In the market," he lamented, "there's no energy, no life."
At the Damascus Restaurant, a Syrian fighter hangout across from Antakya's main hospital, several broad-shouldered men squeezed together on tiny, vinyl-covered stools. One wounded fighter started griping about how he had an X-ray for his back and then was rudely hustled out of the hospital.
"It's been 20 days, 20 days, and I still haven't heard anything," he said. "We have an expression in Syria: You either host your guest properly, or you don't host them at all."
At that, a local official within earshot pulled him away from the group and said: "What are you talking about? You're eating the bread of this country. Don't complain."
A few minutes later, a police van pulled up, disgorging half a dozen beefy Turkish police officers. The Syrian fighters scooted.
In a way, the two neighbors could not be more different: Turkey, democratic, highly nationalistic, orderly and on its way up, versus Syria, authoritarian, deeply divided and plunging into a messy civil war.
Many Syrian rebels here, when asked why they defected, began their answer with the same word: "atfal," Arabic for children.
"The government is slaughtering children," said Mulham al-Masri, a former captain in the Syrian Army who defected a few months ago.
He said he had been plotting his escape for weeks, talking to a cousin in the Free Syrian Army via cellphone and then walking out of his barracks one morning, in full uniform, and slipping into a black Hyundai stuffed with rebels.
One of his comrades, Nabil al-Amouri, also formerly an officer in the Syrian Army, said many other officers wanted to defect, but they were worried about revenge. "These guys have killed civilians, and they're now afraid of the families," Mr. Amouri said.
Every night, the border is bustling along illegal crossing points. Medicine and supplies flow into Syria, and bloodied fighters trudge out.
But Antakya used to be a hot weekend destination for Syrians coming across to shop. One tourist operator said he used to get 2,000 customers per day, but now it is down to zero. The operator, who did not want to be identified because he was embarrassed about going bankrupt, said he had just laid off the last of his three secretaries.
"This conflict did not affect us," he said. "It finished us."
Sebnem Arsu contributed reporting.
This article originally appeared in The New York Times.