A Turkish news channel says a video that appears to show the man assisting the three girls was filmed in Gaziantep, on Turkey's border with Syria.
A Turkish government official, speaking on condition of anonymity because he was not authorized to comment, confirms the video came from the police.
Turkish Foreign Minister Mevlut Cavusoglu says the suspect — who is in custody — helped the teenagers even though he worked for the intelligence agency of a country that is part of the coalition fighting ISIL.
Cavusoglu didn't identify the country, but says it wasn't the U.S. or a European Union member.
CBC News reported from Istanbul that Mohammad Al Rashed, a Syrian who purportedly went by the alias Dr. Mehmet Resit, allegedly helped the girls cross from Turkey into Syria shortly after they arrived from London on Feb. 17.
Citing a witness statement in a Turkish intelligence report, CBC said the man claims he worked for Canadian intelligence and travelled occasionally to the Canadian Embassy in Jordan to share information he had gathered.
Earlier this week, a European security source familiar with the case told Reuters the person in question had a connection with the Canadian Security Intelligence Service.
In the House of Commons, NDP deputy leader Megan Leslie led off question period with the issue for the second consecutive day.
"Can the government confirm that someone linked to Canadian intelligence, either an employee, an agent or an asset, is being detained in Turkey?" she asked.
Roxanne James, parliamentary secretary to the public safety minister, said while the government was aware of the reports, she could not comment on operational matters of national security.
Leslie noted Bruno Saccomani, the former head of the prime minister's security detail, is now Canada's ambassador to Jordan.
CSIS has referred questions about the matter to the Public Safety Department. Neither Public Safety nor Foreign Affairs would comment Friday.
NDP foreign affairs critic Paul Dewar urged the government to figure out what took place, saying it would be a "big problem" if Canada had been involved with someone "working for the enemy."
In the video shown by Turkish broadcaster A Haber, a man speaking in English appears to tell the British girls that they will be in Syria within an hour.
The three girls — identified by British authorities as Shamima Begum, 15, Kadiza Sultana, 16, and 15-year-old Amira Abase — travelled from the U.K. to Turkey last month.
Earlier this month, Turkish TV obtained video showing the teenagers in Istanbul before they boarded a bus.
— With a file from the Associated Press
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