CEYLANPINAR, Turkey: Aware of the danger but drawn by curiosity, men huddled on a rooftop and gawped as artillery rounds crashed into the earth, yards from the flimsy fence that separates this Turkish border town from Syria.
"This war is not just in Syria, it is now here in Turkey. It is in Ceylanpinar," said 26-year-old Ahmet Kayakiran. "What border? There is no border any more," he said, as the concrete roof shuddered with every impact.
In the 20 months since the revolt against President Bashar al-Assad began, one by one the sleepy Turkish towns and villages up and down this 900-km (550-mile) frontier have watched helplessly as the Syrian war edges ever closer.
The proximity is no more obvious than in Ceylanpinar, where what was a single town under the Ottoman empire was split after World War I, with part remaining in the new Turkish republic and part coming under French rule in what would become Syria.
Ras al-Ain, as the town on the Syrian side of the frontier is known, was overrun on Thursday by anti-Assad rebels advancing into Syria's northeast, home to many ethnic Kurds. Fighting has sent thousands of refugees fleeing for safety in Turkey.
No sooner had the rebels raised their flag over Ras al-Ain after a fierce battle, however, than Syrian government tanks and artillery began firing back into the town in what has become an all too familiar pattern of the civil war.
Assad's forces unleashed their air power on Monday, a warplane screeching along the frontier and bombing close to the border fence, sending scores more Syrians scrambling over into Turkey. Helicopters strafed targets for a second day.
Turkey does not want to become embroiled in a regional war, but risks being drawn in by domestic pressures. As frustration grows among leaders in Ankara at world powers' failure to stop the bloodshed, so too are Turkey's citizens becoming impatient with their own government's inability to keep them safe.
Like Ahmet Kayakiran's, flat-roofed Syrian and Turkish houses abut the barbed-wire fence that divides the two modern towns, whose combined population is 80,000 and between which Arabs and Kurds have long maintained family and social bonds.
Though crossing the frontier has often been limited by official restrictions, friends and relatives exchange greetings through the wire as though chatting over a backyard fence.
Loitering near the wire is now a risky pastime, however. Kayakiran's uncle, Mehmet Ali, recalled how close the war came when, after rebels took Ras al-Ain last week, he stepped outside his home in Ceylanpinar to phone a friend over the border.
"I wanted to see if he was alive," he said. "I was just putting the phone to my ear when the bullet hit right here," he said, pointing to a street sign nailed to the wall of his house.
The stray bullet, fired from across the fence, left a small dent in the metal panel inches from where his head had been.
"That's nothing," said a neighbour joining the conversation. "My wall is riddled with bullet holes."
Others have been less fortunate; two people in Ceylanpinar were wounded last week by stray bullets fired from Syria, including a teenage boy who was shot in the chest.
Around 100 km (60 miles) west along the border, in the Turkish town of Akcakale, five civilians were killed last month when a mortar fired from Syria struck their home.
It was the most serious cross-border incident since the fighting began, spurring Turkish calls for more robust action from world powers, including the possible deployment by NATO of Patriot surface-to-air missiles on the Turkey-Syria border.
Turkey says it has fired back in retaliation, but its calls for a buffer zone to be set up inside Syria have so far failed to gain traction among reluctant Western powers.
As in Akcakale, many of those in Ceylanpinar living near the fence have abandoned their homes for the time being. The neighbourhood resembles a ghost town, where Turkish soldiers in trenches train their guns on Syria.
Turkish police trucks armed with water cannon, typically used in the past to suppress the restive ethnic Kurdish population of southeastern Turkey, including Ceylanpinar, now patrol the Syrian border.
Police warn children not to play near the fence. Schools have been closed since last week, and over loudspeakers on Monday authorities urged people to stay indoors.
"We've locked our doors and left," said Huseyin Albayrak, a neighbour living a few doors down from Kayakiran. "I've sent my wife and kids to my father further inside the town.
"Turkey needs to do something to protect its people."