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.
The Syrian Observatory for Human Rights said one person was killed and others injured. The witness said two were killed and 25 injured.
Iranian Defence Minister Amir Hatami travelled to Damascus on Sunday for a two-day visit.
Iranian forces have backed Syrian President Bashar al-Assad in the country's civil war.
President Bashar al-Assad is aiming to restore control over rebel-held areas at the borders with Jordan and the Israeli-occupied Golan Heights.
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.
Syria's President Bashar al-Assad denied Moscow is running the show in his war-torn country, saying in an interview released Sunday his government operates independently of its Russian and Iranian allies.
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.