GENEVA (Reuters) - More than 600,000 Syrians returned to their homes in the first seven months of this year, nearly as many as in all of 2016, but they are still outnumbered by those freshly displaced, the U.N. migration agency said on Friday.

Many went back to their areas of origin to check on property or because they had been in places where the economic and other conditions were deteriorating, the International Organization for Migration (IOM) said.

"The returns are not confirmed as voluntary, safe or sustainable," IOM spokeswoman Olivia Headon told a briefing.

About 67 percent of the returns this year have been to Aleppo province - where the rebel-held eastern part of the city was retaken by the Syrian government in December - IOM said.

Most of the 602,759 Syrians who returned to their homes between January and July had been uprooted within their war-torn homeland, with the other 16 percent returning from Turkey, Lebanon, Jordan and Iraq, Headon said.

The number nearly matched the 685,662 people who returned during all of 2016, she said.

But an estimated 808,661 people have been newly displaced this year, "many for the second or third time," she said.

In all, more than 6 million people currently remain displaced within Syria.

(Reporting by Stephanie Nebehay; Editing by Toby Davis)