The official said that Kary Paul Kleman was detained after surrendering to border guards at the Oncupinar crossing in Kilis. He was accompanied by his wife, a Syrian national, and three children.
"Our initial assessment is that he along with his family members was compelled to escape the conflict zone following airstrikes and military operations against ISIS," the Turkish official told CNN.
A US official confirmed Kleman was arrested trying to cross back into Turkey through Killis alongside a British national and that man's wife.
Because of the large number of foreign fighters that have transited across the Syrian-Turkey border
, Turkey has detained a significant number of individuals crossing back into Turkey from Syria, to question them about their time there.
According to the Guardian newspaper, which was the first to report on Kleman's detention at the Turkish border, he was previously a Florida resident. Kleman's family told the newspaper he converted to Islam after divorcing his first wife and moved to the Middle East in 2011.
The family said he traveled to Syria in 2015 to help with humanitarian efforts, but after he arrived there he realized the information that had led him there "was all a scam," the Guardian reported. The family told the newspaper he had recently been in contact with US officials in Turkey, and had planned to reach the American embassy there and return to the US. Relatives said they alerted the FBI that he may be in danger about 18 months ago, and they had told the family they were vetting whether he had become involved in any wrongdoing, the Guardian reported.
CNN on Wednesday communicated with a smuggler in Azaz, Syria who says he spent time with Kleman in Syria, after the family escaped from ISIS-controlled territory about six months ago. Azaz is just across the border from Killis. He told CNN he also helped the British man detained by Turkey, whom he identified as Stefan Aristidou, a man he said was of Cypriot descent. The smuggler said he put the American and the British man in touch with other smugglers to get them out of Syria. Aristidou has also been identified in British media reports as a native of Enfield, in north London.
The smuggler said that Kleman, his Syrian wife, and children, along with Aristidou and his wife and five-month-old child, were smuggled out of Syria on April 20. The smuggler said a humanitarian charity group played a role in getting them across the border into Turkey.
The smuggler said he had no idea what happened to them after they left Syria. The smuggler told CNN that Kleman married his Syrian wife in the United Arab Emirates several years ago.
The smuggler provided CNN with a copy of what he said was Kleman's United States passport photo page, which he said Kleman handed to him while he was still in Syria. The passport was issued in April 2010 and says Kleman was born in Wisconsin on July 23, 1970. The smuggler said the American told him he had come to live in Caliphate territory, where he lived for about a year, but never swore allegiance to ISIS leader Abu Bakr al Baghadi nor became an active fighter.
"He doesn't know how how to use a gun." the smuggler said.
Kleman told the smuggler he lived in the village of Bezaa just northeast of the Syrian town of al-Bab, which was an area under ISIS control until a Turkish offensive in February 2017.
At a certain point, it appears that Kleman wanted out. The smuggler said that Kleman contacted a family member in the United States to get help in escaping from ISIS territory. Later, Kleman spoke with someone at the CIA but they never got back in touch with him, the smuggler claimed, adding that according to what he understood from Kleman, the FBI was also involved in the case.
Kleman appears to have been a longtime resident of Jacksonville, Florida. A Jacksonville resident by the same name was interviewed in 2005 by the Florida Times Union recalling a 2001 visit to Mecca, Saudi Arabia, to carry out the Hajj pilgrimage.
The smuggler said the British man Aristidou arrived in Azaz from ISIS territory eleven months ago. In an interview with Sky News last month Aristidou claimed he went to live in ISIS territory for religious reasons rather than to fight and had decided to escape after life there became like a "prison."
CNN's Elise Labott contributed to this report.