Turkey has confirmed it is deploying more fighter jets to an airbase close to the border with Syria, amid artillery exchanges along its tense southeastern border with Syria.

The announcement came amid reports of fierce fighting in the northern Idlib province on Tuesday where Syrian rebels are trying to take control of a strategic town.

"Assad ... is only able to stand up with crutches," Recep Tayyip Erdogan, the Turkish prime minister, who was once a close ally of Syrian President Bashar al-Assad, told a meeting of his ruling AK Party.

"He will be finished when the crutches fall away."