Turkey, which supports rebels opposed to Syrian President Bashar al-Assad, has been holding talks with his allies Russia and Iran over the fate of Idlib.
Anadolu said that during his questioning, Yusuf Nazik confessed to having received orders from Syrian intelligence to plan an attack in Turkey.
The northern province and surrounding areas are the last major swathe of territory held by insurgents fighting Syrian President Bashar al-Assad.
Iranian forces have backed Syrian President Bashar al-Assad in the country's civil war.
A war monitor reported Syrian military helicopters dropped barrel bombs on rebel-held areas of the southwest on Friday for the first time in a year.
The president was surrounded by dozens of worshippers who appeared to be offering him Eid greetings.
The government on Monday seized the Yarmuk Palestinian camp and adjacent neighbourhoods of Tadamun and Hajar al-Aswad, putting Damascus fully under its control for the first time since 2012.
The Syrian Observatory for Human Rights said there was intense fighting on several fronts accompanied by a government artillery barrage, continuous air raids and attacks by helicopters.