"There is no satisfactory plan that is put before us concretely yet," Erdogan told a parliamentary meeting of his AK Party, Reuters reported.
"Of course we are loyal to our agreements, our promise is a promise. But our patience is not limitless."
Turkey wants the zone to be cleared of the US-backed Kurdish YPG militia which Ankara considers a terrorist group.
Erdogan also said that if terrorists are not removed from the northern town of Manbij in a few weeks, Turkey's waiting time will end.