“We are fleeing from the rebels, and the camps are full of rebels,” said the mother of the three little boys, a schoolteacher who did not want to be named for fear of rebel reprisals against relatives at home.

Many of the Christian refugees are young men who have fled conscription in the army and now fear being drafted into rebel ranks if they enter the Turkish camps, Evgil Turker, the president of the Federation of Syriac Associations in Turkey, said in an interview.

Al Nusra Front “and other rebel groups are entrenched in the refugee camps,” Mr. Turker said. “They round up young men in the camps, sometimes 20 or 30 a day, and send them through the border fence back into Syria.”

Mr. Turker’s organization has retrieved dozens of Syriacs from the camps, where some of them are sent by Turkish security forces when caught crossing into Turkey illegally. “We vouch for them and they are released to us on our recognizance,” Mr. Turker said.

The Syriac community of Turkey, itself greatly diminished by persecution and emigration over the last century, has rallied to come to the aid of fleeing kin and coreligionists from Syria. Besides rescuing refugees from the camps, the Syriac community shelters them in monasteries and in dozens of church properties and privately owned vacant houses in Tur Abdin. Donations from local Syriacs and from the large Syriac diaspora in Europe keep the refugees fed and clothed.

“We can handle it so far,” said Ayhan Gurkan, deacon of the Mor Barsomo church in Midyat and vice president of the Syriac Culture Association, who runs aid distribution in Midyat. “But God help us if the insurgents take the Jazeera from the Kurds. Then we will be overwhelmed.”

That is an imminent danger, according to refugees sheltering in the Mor Hobil-Mor Abrohom monastery outside of Midyat. While the Kurds remained in control of the Jazeera, most Syriacs would stay put, said one young man, who gave his name only as Gabriel. But if the region should fall to Islamist Arab rebels, “then not any Christian people will stay there,” he said.