Russia, Turkey, and Iran failed to agree on de-escalation zones in Syria during peace talks conducted in Kazakhstan, diplomats said Wednesday.
Russia and Iran, which support Syrian President Bashar al-Assad, had agreed to work with Turkey, which backs the rebels, to establish four "de-escalation" zones in the war-torn country.
The three hope to reach a consensus by the end of August, when they will reconvene in Astana.
Wednesday's failure is a setback for Moscow, the organizer of the peace talks, as it seeks to take a leading role in global efforts to settle the six-year war in Syria.
"During these consultations the Turkish side said it needed more time in order ... to make an appropriate decision," said senior Russian negotiator Alexander Lavrentyev.
Bashar al-Ja'afari, the lead negotiator from the Damascus government, was more direct in his comments on the Turkish position.
"The Turkish delegation objected to the adoption of any documents related to the implementation of mechanisms of the agreement on the de-escalation zones," he said.
Turkish delegates made no statement after the talks, but Turkish president Recep Tayyip Erdogan said in an interview with France 24 later Monday that he would discuss the issue with Putin on the sidelines of the G-20 summit in Hamburg this week.
Previous rounds of talks in Kazakhstan, convened in parallel with U.N.-brokered peace talks in Geneva, have not made substantial progress. A cease-fire declared in May, built around so-called "de-escalation zones," has been repeatedly violated.
The Syrian civil war has killed more than 320,000 people, according to U.N. estimates, and the world body has established a commission of inquiry to document cases of torture, summary killings and other atrocities by all sides in the conflict.