Syria's opposition pledged not to walk away from a new round of peace talks in Geneva on Tuesday despite rebel defeats in Damascus and US charges of regime atrocities at an infamous prison.
The sixth UN-backed round of talks got under way after Syria's government secured the evacuation of three rebel-held districts of Damascus through so-called "reconciliation deals."
The opposition has blasted these agreements as forced displacement, but the opposition said it was committed to seeing the negotiations through.
"We will not walk away from Geneva or anywhere as long as we see on the horizon a solution for our people," High Negotiations Committee (HNC) spokesman Salem al-Meslet told AFP.
According to Meslet, HNC members discussed two main topics during their first meeting with UN special envoy Staffan de Mistura on Tuesday afternoon: a constitution for Syria, and thousands of prisoners in regime jails.
"We focused on the issue of releasing detainees, and de Mistura focused on the constitution. No draft was presented during the meeting," Meslet said.
A new Syrian constitution is one of four separate "baskets" that UN-backed talks are focused on, in addition to governance, elections and combating "terrorism" in the war-ravaged country.
De Mistura met with the government delegation, headed by Syria's ambassador to the UN Bashar al-Jaafari, on Tuesday morning.
The opposition and regime sat down for face-to-face talks in 2014 but have since only held indirect negotiations.
Meslet on Tuesday said the HNC was willing to go back to direct interactions.
"If the other party cares about the lives of Syrians then we will sit (at) the same table in the presence of Mr. de Mistura and discuss all issues. We want a solution that ends this disaster in Syria," he told AFP.
Tuesday was the first time warring parties in Syria returned to Geneva since a landmark agreement was reached to create four "de-escalation zones" across some of Syria's bloodiest battlegrounds.
The May 4 agreement was signed in Astana, Kazakhstan by opposition ally Turkey and regime backers Russia and Iran.
Observers have noted that the growing momentum of the Astana track was putting additional pressure on parties in Geneva, but Meslet told AFP that a final political solution would only come through UN-backed talks.
"We only believe in deals that are agreed upon here in Geneva -- not in Astana," he said.