US-led strikes kill 15 civilians in northeast Syria: monitor
Writing on his Facebook page, Rami Jarrah said he had been released but said he was given no explanation as to why he was arrested, though he added it appeared to be related to his work in Syria.
Jarrah was detained by Turkish authorities on Wednesday, according to the Committee to Protect Journalists, a rights group that had called for his release.
France's Hollande warns of risk of Turkey-Russia war over Syria
He was held while applying for a residency permit in the southern Turkish city of Gaziantep.
Turkish authorities had no comment on his reported detention.
Ankara is a key backer of Syria's opposition and says it is hosting more than 2.6 million Syrian refugees.
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