Astana (Kazakhstan) (AFP) - Russia, Iran and Turkey on Thursday signed an agreement on setting up four safe zones in Syria that the United Nations described as a promising step to wind down the brutal six-year war.
The United States however gave an extremely cautious welcome, citing concerns over Iran's role as a guarantor, even as it expressed hope that the deal could set the stage for a settlement.
Several members of the rebel delegation left the room shouting in protest as the signing ceremony got underway in the Kazakh capital Astana, angry at regime ally Iran, an AFP reporter saw.
The plan for the "de-escalation areas" was discussed on Tuesday by US President Donald Trump and Russian President Vladimir Putin during a telephone conversation.
The agreement provides for a ceasefire, a ban on all flights, rapid deliveries of humanitarian aid to the designated areas and the return of refugees.
UN Secretary-General Antonio Guterres said he was "encouraged" by the breakthrough. He stressed it will be "crucial to see this agreement actually improve the lives of Syrians."
Russia and Iran, which back Syrian President Bashar al-Assad's forces in the war, and Turkey, a supporter of rebel forces, hope to build on a ceasefire deal they reached in December.
The Syrian government and rebel delegations are not signatories to the deal.
"We are not supporting this agreement. It is an agreement between the three countries," said Usama Abu Zeid, a rebel spokesman. "We do not at all agree that Iran... is a guarantor of this accord." READ MORE