Turkish Prime Minister Tayyip Erdogan said the uprising against Syrian President Bashar al-Assad is "closer than ever to victory" and warned that Turkey will respond firmly to any hostility from Syria.
Turkey has called for Assad to quit after he failed to heed calls for reform and the country has harboured Syrian rebels and tens of thousands of refugees along its border with Syria.
Tensions between the two countries, which previously enjoyed warm ties, rose sharply last month when a Turkish jet was shot down by Syrian air defences.
Ankara subsequently increased its military presence, sending anti-aircraft missiles to the border and scrambling planes when Syrian aircraft came close to Turkish territory.
"We believe that the Syrian people are closer than ever to victory," state-run Anatolian news agency quoted Erdogan as saying at a dinner for ambassadors in Ankara on Monday evening.
The Turkish prime minister also criticised the faltering peace plan drawn up by international envoy Kofi Annan after the UN Security Council voted on Friday to extend for 30 days the mandate of the UN monitoring mission in Syria.
"The Annan plan, which the international community including Turkey has supported in good faith, has become a vehicle for exploitation by the Assad regime in its current form. The international community must take more responsibility when faced with the unfolding developments," he said.
Erdogan also issued a new warning to Syria, calling on it to heed Turkey's firm response to the shooting down of the Turkish military reconnaissance aircraft on 22 June off the coast of Syria.
"If the Syrian regime does not learn the lesson of these developments and continues its hostile behaviour, Turkey will not hesitate to give as good as it gets," Erdogan said.
Syria says it shot down the F-4 jet in self-defence without knowing that it was a Turkish aircraft after it flew into its air space at high speed and low altitude.
Turkey has said it violated Syrian air space accidentally for a few minutes but maintains its plane was shot down by a missile without warning in international air space off the Syrian coast.