Syrian regime allies Russia and Iran and rebel supporter Turkey on Thursday signed a memorandum on a Moscow-backed plan to create safe zones in Syria to bolster a fragile truce.
But as officials form the three countries backing rival sides in the conflict signed the agreement on Thursday at the Syria cease-fire talks in Kazakhstan, some members of the Syrian opposition delegation shouted in protest and walked out of the conference room in Astana, the Kazakh capital.
The opposition has protested Iran's participation at the conference, accusing it of being a party in the war that's killed some 400,000 people.
The Kazakhstan agreement calls for setting up four zones in northern, central and southern Syria. However, no details were provided about how violence will be reduced in these areas.
"Over the past two days, the participants in the Astana talks reviewed the implementation of the ceasefire agreement and the cessation of hostilities," Kazakhstan's foreign minister Kairat Abdrakhmanov said of a frail truce brokered by Moscow and Ankara in December.
"As a result the guarantor countries agreed to sign a memorandum on the creation of de-escalation zones in Syria."
Syrian rebels said earlier Thursday that they had resumed participation in the talks after having suspended their involvement a day earlier over air strikes against civilians.
After talks with Turkey counterpart Recep Tayyip Erdogan on Wednesday, Russian President Vladimir Putin said the safe zones were meant to lead to "further pacification and cessation of hostilities."
He also said the proposed zones would also be no-fly areas if fighting on the ground there stopped entirely.
The Kremlin's plan echoes calls by US leader Donald Trump to establish safe zones in Syria.
Putin said Wednesday that "as far I could tell" the US leader broadly supported the idea in a phone call they held on Tuesday.
Erdogan said in comments published Thursday that Moscow's plan to set up these zones in Syria would "50 percent" solve the six-year conflict.
Damascus supports the Russian plan, Syrian state news agency SANA reported.
More than 320,000 people have been killed in Syria since the country's war began with anti-government protests in March 2011.