Most returned to Aleppo, Hama, Homs and Damascus, it said, on the view that security had improved in parts of the country.
"This is a significant trend and a significant number," UNHCR spokesman Andrej Mahecic told a Geneva news briefing.
"Most of these people are returning to check on properties, to find out about family members... They have their own perceptions about the security situation, real or perceived improvements in areas they returning to."
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