Since US President Donald Trump withdrew American troops from northern Syria, he has been criticised for abandoning the Kurdish people and Christians in the region and leaving them open to attack from Turkish forces.
Turkish-backed fighters have been advancing in northern Syria since last month, leading to the displacement of about 200,000 people.
A car bomb went off in Tal Abyad on the Turkey-Syria border this week, injuring 20 people according to the Turkish defence ministry, who also blamed Syrian-Kurdish fighters for the attack.
Some Christians are also mistreated by the Kurds, but are united in their opposition to Turkey entering the area.
On Saturday, the Kurdish-led Syrian Democratic Forces (SDF) said Christian fighters would now oversee security in a northern Syrian region that has witnessed fighting between Turkey-backed troops and Kurdish-led militiamen.
The SDF said the deployment will take place in villages close to the town of Tal Tamr in the Khabur river region, an area home to Syria's dwindling Christian Syriac and Assyrian communities.
The Syriac Military Council, a founding member of the SDF, said on Sunday that it had taken the decision to continue defending itself against attack but demanded the ceasefire be enacted to "save the area and its residents from further distraction and atrocities" and called on the international community to protect the rights of its "ethnic and religious groups".
There have been concerns in Christian villages about possible atrocities by Turkey-backed fighters, which include former jihadists.
Elizabeth Kourie from the Syriac Christian Movement in northeast Syria said Turkey's President Erdogan was trying to ethnically cleanse the region and "commit massacres against our people".