This is reported by RIA Novosti with reference to the Communications Department of the Presidential Administration of Turkey.
The report says that the meeting will discuss steps to end the conflict in Ukraine through diplomacy, "by revitalizing the mechanism created to export Ukrainian grain to world markets."
Earlier, the spokesman for the UN Secretary General, Stephane Dujarric, said that Guterres would meet with Zelensky and Erdogan in Lviv on August 18.
Russian presidential spokesman Dmitry Peskov said in June that a peace plan was possible after Kyiv met all of Moscow's demands.