President Recep Tayyip Erdogan said Turkey is seeking to hold a summit in Istanbul with France, Germany and Russia on September 7 to discuss regional issues including the Syrian conflict, in comments published on Sunday.
"We will discuss what we can do in the region together," Mr Erdogan said, quoted by Hurriyet daily.
He gave no further details on the issues on the agenda but said Turkey would continue dialogue with Russia, "outside of this foursome", in the remarks made to Turkish journalists during his South Africa visit on July 25-27.
Mr Erdogan met with Russian President Vladimir Putin during the visit on the sidelines of the Brazil, China, India, Russia and South Africa summit of leading emerging economies in Johannesburg.
"We will separately have a summit in Istanbul on September 7 with Russia, Germany, France and Turkey", Mr Erdogan was quoted as saying.
There was no immediate confirmation from Moscow, Paris or Berlin.
The seven-year conflict in Syria is likely to be high on the four countries' agenda as Russia, Iran and Turkey continue their efforts to end the war under the Astana peace process launched last year despite being on opposing sides.
While Moscow and Tehran support Syrian President Bashar Al Assad's regime, Ankara has repeatedly called for his ouster and helped Syrian rebels.
In April, Mr Erdogan held a summit with Mr Putin and Iranian counterpart Hassan Rouhani in Ankara.
The three leaders are due to meet again in the near future in Tehran, Mr Erdogan said without giving an exact date, while technical talks as part of the Astana process will take place on Monday and Tuesday in the Black Sea resort of Sochi in Russia.