"Turkey has the right to eliminate all threats against its national security," he said in a televised speech in Ankara.

"God willing, we will carry the process started with (previous offensives into Syria) to the next stage very soon."

As he spoke, American and Turkish defence officials were locked in talks in Ankara.

The United States, which has supported the Kurdish YPG as the main fighting force against the Islamic State group, hopes it can convince Turkey to avoid a military intervention by reaching agreement on a buffer zone in northern Syria.

So far, Turkey has been unimpressed with the US proposals.

"Turkey expects steps from the US befitting of a NATO ally and strategic partner," Erdogan said.

"Turkey has the right to eliminate all threats against its national security. Drying up the terrorist swamp in northern Syria is our top priority," he added.