Civilians have been evacuated from four besieged towns in Syria
People living in the north-western towns of Foah and Kefraya are being evacuated to government-held areas close to Aleppo.
The deal, which began on Wednesday following a delay, is an an exchange of prisoners between rebels and government forces.
The towns of Madaya and Zabadani are also being evacuated, but civilians will be allowed to remain there if they want to.
The two towns have been besieged by the army of President Bashar al-Assad and allied fighters from Hezbollah, the Lebanese armed group, since June 2015.
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A Madaya resident, Hoissam Mahmmoud, said: “I left my mother behind. She refused to leave her home and her land.
"Two years under siege, huge, air strikes, cold and rain has ended with displacement. We do not know where we are going to live.”
A Madaya resident who travelled in one of the evacuation uses said: “We just left now – around 2,200 people in around 65 buses.
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“Most of the passengers are women and children who started gathering yesterday evening and spent the night in the cold waiting.”
The United Nations has described the situation in the four towns as “catastrophic” because of the 64,000 civilians trapped with people dying because of the shortages of food and medicine.
There are 4.7 million people live in besieged areas in Syria, which is in the seventh year of conflict.
Over the past year, the Syrian President Bashar al-Assad’s government has allowed rebels and their families to leave opposition-held areas.
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Critics have claimed the deal is a forced replacement and the United Nations is not supervising the evacuations.
They are concerned that the population movements are changing the ethnic and religious map of the country.
However, President al-Assad said the move is temporary and people would return to their homes after the “terrorists” had been defeated.
He said: “We wish that everyone could stay in his village and his city, but those people like many other civilians in different areas were surrounded and besieged by the terrorists, and they've been killed on (a) daily basis, so they had to leave.
“But of course they're going to go back to their cities after the liberation.”