The failure of Syria peace talks this week has cast doubt over UN efforts to mediate a solution to the country's devastating war, while regime backer Russia has emerged as a key dealmaker, analysts say.

The latest round of Geneva-based talks aimed at ending the nearly seven-year conflict, which has killed more than 340,000 people, ended Thursday in failure.

UN mediator Staffan de Mistura acknowledged that "real negotiations" never took place during the eighth round of talks.

"I am disappointed," he said, blaming the Syrian government for refusing to enter into dialogue and calling the round "a golden opportunity missed".

Seven previous rounds of talks mediated by de Mistura have also gone nowhere -- and under his watch the rival sides have never met for face-to-face negotiations.

The discussions have repeatedly stumbled over the fate of President Bashar al-Assad, and Damascus is refusing to meet the opposition directly until it drops demands that he leave office.

For their part, the opposition and western diplomats are concerned that parallel Moscow-backed talks are an effort to circumvent the UN talks and impose a solution favourable to Assad after major battlefield gains by Russian-backed regime forces.

- 'On life support' -

"The balance of power undeniably favours the Russians," Karim Bitar of the Paris-based Institute of International and Strategic Affairs told AFP, adding that the Geneva talks appeared to be "on life support".

Bolstered by Russia's intervention in 2015, Damascus has regained the upper hand militarily, retaking large swathes of rebel-held territory.

Russian-backed Syrian forces have also dealt severe blows to the Islamic State group, whose self-proclaimed "caliphate" in Iraq and Syria has largely collapsed.

As regime forces advanced on the ground, Moscow, along with fellow Syrian ally Iran as well as rebel-backers Turkey, have organised talks on halting the fighting, which are set to resume next week in Astana, Kazakhstan.

Those talks have resulted in "de-escalation zones" and ceasefire deals that critics say have been imposed in a manner that largely serves to consolidate regime gains.

Diplomats warned that a meeting organised by Moscow for early next year in the Russian Black Sea resort of Sochi might further ease the pressure on Assad as well as undermining the Geneva talks.

A European diplomat, who asked not to be identified, said the Sochi meeting could be "a stitch-up and a tendentious attempt to invite the wrong people to discuss the wrong issues (and) create the wrong kind of consensus."

Bitar said the idea was "to legitimise, to consecrate diplomatically, if not to consecrate legally, this balance of power."

- 'Treading water' -

The government and opposition delegations both insisted Thursday that they were committed to the Geneva talks, with de Mistura voicing hope he could convene a ninth round in January.

Nasr al-Hariri, the chief negotiator for the opposition, said the Swiss city remained "the only place to reach a political solution" but warned that with international institutions "held hostage" by the regime and its backers, yet another round would probably be fruitless.

The Syrian government's top negotiator, Bashar al-Jaafari, said that "we don't want the Geneva track to fail", though he denounced the opposition and its backers for sabotaging talks with demands for Assad to step down.

But the European diplomat said the failure of the latest round of talks had raised "profound questions" about the government's commitment to the process.

"I think we are treading water at the moment," he said.

"To some extent we can only tread water so long as the regime feels impunity and no pressure to negotiate."

On Wednesday de Mistura urged Russian President Vladimir Putin to push Damascus to accept new UN-monitored elections.

But his comments sparked a fierce backlash from the Syrian government delegation, which accused him of "undermining" his position as mediator and threatening "the entire Geneva process".

But for Nikolay Kozhanov, a professor at the European University in St Petersburg, Geneva is "not playing a key role at the moment".

"It's more important to reinforce de-escalation zones and local ceasefires and work with the groups that actually affect the situation on the ground, and with the forces that can influence them," he said.

But Kozhanov also questioned how much sway Russia had over the situation.

"Moscow's influence on Assad is limited," he said. "Assad shouldn't be seen as Russia's puppet."

Source: AFP