Turkey said on Friday that information collected by its secret services meant there was "no doubt" that the Syrian regime was behind a chemical attack on August 21.
Turkish Foreign Minister Ahmet Davutoglu told a press conference: "From our point of view, based on evidence gained by our intelligence services and experts... there is no doubt, it is clear the regime is responsible."
Turkey has continually pointed the finger at those loyal to Bashar al-Assad since the deadly attack but this is the first time Ankara has used evidence from its intelligence services to back up the claim.
Davutoglu added that only the forces of the Syrian regime possessed the "sophisticated systems" needed to fire the chemical weapons with such precision.
Syria's opposition has accused Assad's regime of launching a massive chemical bombardment in the early hours of August 21 which, it said, left up to 1,300 people dead.
The minister also called on the international community to "present an initiative which would end the war in Syria", in apparent reference to any multilateral action against Syria.
He also criticised the lack of agreement internationally.
"Unfortunately after 10 days (since the attack), we have not been able to reach an agreement," he said, adding that if the August 21 attack went unpunished, the Syrian regime would continue its policy of "massacres".
Turkey, which is a member of NATO, is opposed to the Syrian regime, its former ally, and is committed to joining an international response, even without a consensus.
Earlier this week, Turkish protestors took to the streets to try and halt any response to Syria.