By Denis Dyomkin and John Irish
ASTANA (Reuters) - Syria's warring sides met for their first talks in nine months on Monday, with their Russian and Turkish backers pushing to cement a ceasefire that could pave the way for political talks.
The meeting in the Kazakh capital comes at a time when Turkey, which backs the rebels, and Russia, which supports Syrian President Bashar al-Assad, each want to disentangle themselves from the fighting.
That has led them into an ad-hoc alliance that some believe represents the best chance for progress towards a peace deal, especially with the United States distracted by domestic issues.
After facing each other to make opening remarks on Monday, the rival delegations spent the rest of the day negotiating indirectly through intermediaries and at times trading barbs. But the rebel side expressed optimism about Moscow's position.
"We noticed a real understanding on the part of the Russians," Yahya al-Aridi, an opposition spokesman, told reporters.
"We understand that militarily they have achieved what they wanted in Syria. Now they want to translate this military achievement into some sort of political deal. That has to be a ceasefire."
Diplomats said Russia, Turkey and Iran were working on a final communique that could be completed as early as Tuesday. It would reaffirm a Dec. 30. ceasefire that each side accuses the other of violating.
Russian news agency TASS cited an early draft communique as saying Moscow, Ankara and Tehran would commit to jointly fighting Islamic State and Jabhat Fateh al-Sham, the militant group formerly known as Nusra Front. They would set up a mechanism for trilateral monitoring of the ceasefire.
But fundamental divisions remain between Russia and Turkey which could complicate the final text. Turkey and Russia may also be at odds with Iran, whose militias are core to Assad's military strength and who rebels blame for rights violations.
Mohammed Alloush, a leader of the powerful Jaysh al-Islam group who heads the rebel delegation, insisted he wanted to stop "the horrific flow of blood" in the six-year-old war. To achieve that, the Syrian army and its Iran-backed allies had to abide by the truce and Shi'ite militias had to leave the country.
Bashar Ja'afari, Syria's United Nations envoy, leading the government delegation, said the talks were an opportunity to reconcile the country with Assad staying in power, a red line for rebels. He accused opposition negotiators of defending "war crimes" by Jabhat Fateh al-Sham.
The head of the Russian delegation, Alexander Lavrentyev, told reporters talks had been heated because of the mistrust between the parties, but he remained optimistic that Tuesday could yield results.
Some observers said the meeting, sponsored by Moscow and Ankara with the support of Tehran, could jump-start U.N.-led negotiations that were suspended in April.
U.N. Special Envoy for Syria Staffan de Mistura, attending the Astana talks, said it was crucial to get a mechanism to oversee and implement a nationwide ceasefire.
"That by itself ... would be a major achievement," he said, adding he hoped Astana could pave the way for talks that he has proposed for next month in Geneva.
The rebels' loss of their former urban stronghold, Aleppo, has shifted the momentum of the fighting in favor of Assad.
On Sunday, warplanes bombed rebel-held areas of western Syria, killing 12 people in one location, the Syrian Observatory for Human Rights said, while insurgent shelling of Aleppo killed six.
The Syrian Kurdish YPG militia said on Monday it would not be bound by any decision that came out of the talks in Kazakhstan as it was not involved in the meetings.
The West is playing no role in Astana, although Kazakhstan, with the backing of Moscow and Ankara, extended an invitation to the new U.S. administration last week. The local U.S. ambassador was present, while several Western envoys for Syria were also in Astana to observe developments.
"It's not very serious. You don't seal a ceasefire in two days. You have to work on the modalities, things like observers, mechanisms, maps, the list goes on," said a senior Western diplomat.
But he added: "There is momentum now. The Russians hold the keys. It's now time to use them."
(Additional reporting by Suleiman al-Khalidi, Kinda Makieh and Olzhas Auyezov; Editing by Andrew Roche)