DAMASCUS, July 19 (Xinhua) -- A total of 39 out of 121 buses transporting evacuees from Kafraya and Foa in Idlib province entered Syria's Aleppo province Thursday, a well-informed source told Xinhua.

It was part of a deal reached recently between the rebels and the government that was backed by Iran and Turkey.

The first batch of the buses reached the Eis area in the southern countryside of Aleppo province on their way to the capital city of Aleppo, the source said, on condition of anonymity.

This process will see the evacuation of all the remaining people of Kafraya and Foa, both are predominantly Shiite towns that have been besieged by the rebels in Idlib since 2015.

The deal involves the complete evacuation of all the population in Kafraya and Foa, and in exchange, the government will release 1,500 detainees from the rebels and their affiliates.

The current deal also includes the release of kidnapped people in rebels' custody from the town of Ishtabrak in the northern countryside of Idlib.

The people of Kafraya and Foa had rejected a previous deal for their evacuation last April as they had received no strong guarantees of their safety.

In April 2017, 112 people from both towns were killed while reaching a rebel-held area in Aleppo, when rebels detonated a car bomb near the buses transporting them.

Initial estimates indicated that 3,000 people were to leave both towns, as those were the remaining population of the towns after several batches of evacuation. However, a new estimate suggests that nearly 7,000 people are remaining in the towns.