Vienna: Major power talks on Syria aim to restore a truce across the country and get aid into besieged areas to encourage opposition groups to return to negotiations in Geneva, Germany's foreign minister said on Tuesday.
"We must find a way back into the political process ... It's about improving the conditions for the ceasefire and humanitarian aid so as to win the opposition over to negotiate with the regime in Geneva," Frank-Walter Steinmeier said in Vienna ahead of a meeting of 17 countries backing the talks.
Steinmeier spoke with journalists before the United States, Russia, European powers and Middle Eastern states opened talks aiming to revive a February "cessation of hostilities" agreement that managed to reduce fighting for almost two months.
A recent surge in bloodshed in Aleppo, Syria's largest city before the war, wrecked the partial truce sponsored by Washington and Moscow that had allowed UN-brokered peace talks to convene in Geneva.
The talks collapsed last month after the opposition walked away following an increase in violence. Diplomats say the UN special envoy for Syria Staffan de Mistura hopes to launch a new round of negotiations by the end of May.
He is trying to meet an August 1 deadline to establish a transitional authority for the country that would lead to elections in 18 months.
With humanitarian aid also only trickling through to besieged areas, the main Syrian opposition's High Negotiations Committee has said it would not resume talks until there is tangible progress on the ground.
"We'll need to see the guarantors of the ceasefire - Russia and the US - putting something down that will really convince the opposition that this process is worthwhile," said a senior western diplomat involved in the talks.
"Sadly, I don't sense that and fear the US will try to impose a text that is excessively optimistic, but for which its implementation will not be possible."
The Obama administration's failure to convince Moscow that Syrian President Bashar Al Assad must go is fuelling European frustration at being sidelined in efforts to end the country's five-year civil war, diplomats say.
Some diplomats and analysts question whether the United States has misread Russia's desire to keep Assad in power.
A senior State Department official said the meeting would focus on areas where the truce was most under threat.
"It needs to be on a more solid foundation than it is right now," the official said, adding that the meeting would also focus on increased humanitarian access and on the political process.
Asked about the frustrations of US allies with the current approach, the official said: "Everybody's frustrated. It's not just the allies being frustrated."
"The political deal is going to be done by Syrians at the table ... it still is for Syrians to do. If we can help - all of us can help get the parties there, nudging on both sides to get the parties there, then fine. But they're ultimately going to be the ones that decide this."