"Turks can have the bases they want and do what they want in their own territory and within their borders, but if you talk about … establishing Turkish bases in Syria, that's unacceptable. Said Iranian Foreign Ministry spokesman Abbas Moussavi, quoted by AFP.
Such an initiative would be considered by Tehran as an "aggression against the national sovereignty and territorial integrity of an independent state", he added during a press conference broadcast on state television.
"Of course, it will be opposed by the Islamic Republic of Iran and other countries," Mousavi said.
Iran has repeatedly called at the end of the Turkish offensive, launched on 9 October against Kurdish forces.
Erdogan said on Friday that Turkey plans to establish 12 observation posts in Syria.
He also threatened to resume his offensive if the Kurdish forces did not withdraw from a border area with Turkey as provided for in a truce negotiated on October 17 by Washington.
The truce, which will expire Tuesday at 19:00 GMT, aims to allow the Kurdish militia of People's Protection Units (YPG), considered "terroristBy Ankara, to leave its positions near the Turkish border.
It also aims to enable Ankara to put in place asecurity zone" in this sector.
"We have no intention of staying" in northern Syria, Erdogan said on Friday. "No way".