The UN’s migration agency says over 600,000 displaced Syrians have returned to their homes this year, citing an increasing trend of returns while warning the situation remains “not sustainable,” reported Associated Press.

International Organization for Migration spokeswoman Olivia Headon says the 602,759 returns between January and July was on pace to surpass the figure of 685,000 in all of 2016.

She said however that the 2017 returns were less than the number of displaced this year: nearly 809,000.

IOM said Friday that its partner agencies reporting found that two-thirds went to northern Aleppo governorate, where government forces ousted rebels from the city of Aleppo last year.

Twenty-seven percent of respondents said they returned to “protect their assets” and one-quarter cited “improved economic conditions.”