The deadline for the withdrawal of Kurdish fighters from areas in northeastern Syria expires at 1900 GMT Tuesday, a Turkish military source said, as part of a 120-hour suspension agreed between Ankara and Washington.
"It started at 10pm Thursday... so it finishes at 10pm Tuesday," the source said Monday.
Following the withdrawal, Turkey wants to set up a 120-kilometre (75-mile) "safe zone" between Tal Abyad and Ras al-Ain, they added, saying this will then be extended to 444 kilometres.
Turkey on October 9 launched a cross-border offensive supporting Syrian rebel groups against the Syrian Kurdish YPG militia, viewed by Ankara as "terrorists".
After criticism from the West and US sanctions including raised tariffs on Turkish steel, US Vice President Mike Pence and US Secretary of State Mike Pompeo made a rushed visit to Ankara and agreed on a deal after hours of talks.
The US said that the Kurdish People's Protection Units (YPG) militia would withdraw from the area and Washington would not slap any further sanctions if Turkey ceased fighting.
Pence said the US would lift all of the sanctions, including those slapped on Turkish ministers, following the withdrawal and a complete end to Turkey's military operation.
The Turkish military source said 125 vehicles have left the area so far carrying YPG fighters, taking the route leading to the northeastern city of Hasakeh.
The source added that any "terrorists left" in the 120-kilometre region after Tuesday "will be neutralised".
Turkish President Recep Tayyip Erdogan last week said Turkey would set up 12 observation posts to secure the "safe zone" under Turkish control.
The Turkish defence ministry earlier Monday said five Turkish soldiers have been killed so far during the operation while 86 soldiers have been injured.
The ministry added that 76 members of the "Syrian National Army" fighting with them have died, while 273 fighters have been wounded.