President Recep Tayyip Erdogan's spokesman, Ibrahim Kalin, revealed that the Turkish leader had met separately a second time with Russian and US counterparts Vladimir Putin and Barack Obama before leaving the G20 meeting in Hangzhou.
He said Erdogan had told the two leaders that it was essential "as soon as possible to agree a ceasefire or a truce" for Syria's northern Aleppo province.
Asked when such a truce could be implemented, Kalin said Erdogan had told Putin that the people of Aleppo should benefit from a suspension of fighting in time for the Feast of the Sacrifice (Eid al-Adha) Islamic holiday which in Turkey begins on September 12.
Kalin said that the ceasefire could begin with a 48-hour-truce that would then be lengthened and would see both the regime of Syrian President Bashar al-Assad and opposition fighters halt fire.
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Turkey and Russia have been on opposite sides of Syria's five-and-a-half-year civil war, with Moscow backing Assad and Ankara supporting the opposition against him.
However, there have been signs of a rapprochement on Syria between the two countries after a deal to normalise crisis-hit relations, with Ankara acknowledging Assad could temporarily stay on in a transition.
Turkey has also staged a major incursion inside Syria to back the opposition fighters which it says is aimed at rooting out both Islamic State (IS) jihadists and Kurdish militia on its border.
Meanwhile, Kalin added that there was still no agreement between Turkey and the US over the Kurdish People's Protection Units (YPG), which Washington sees as an ally in the fight against IS but Ankara regards as a terror group.