Syrian opposition chief Ahmad Jarba accused the regime of showing no "serious commitment" during a week of peace talks in Geneva that wrapped up Friday.
"We cannot speak about a serious commitment by Assad's representatives," Jarba told reporters after a first round of closed-door negotiations ended with no concrete results.
Jarba confirmed that his National Coalition will take part in a second round of talks, expected to kick off on February 10.
He stressed though that the opposition's presence in Geneva was conditioned on receiving "the means to defend our people on the ground," according to an official translation of his Arabic speech.
"I can assure you that the pledges made by the states have come into force. The pace of supporting our revolutionaries is quickening, as you may have heard in recent days," he said.
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Media reports have this week alleged that the US Congress had secretly approved funding for weapons deliveries to "moderate" Syrian rebel factions.
The Syrian regime delegation also made the accusation, denouncing the United States for supporting "terrorism".
Washington has not confirmed the information and has dismissed accusations that it supports terrorism as "ludicrous".
Jarba, who headed the delegation but not the negotiating team in Geneva, said it had not been easy sitting down with regime representatives for the first time.
"We felt like we were drinking from a poisoned chalice while the criminal (President Bashar al-Assad) was killing our women, children, young men and women and elderly," he said.
"The only consolation that we had was that the regime which had been oppressing us for more than 50 years had arrived in Geneva to dig its own grave with its own hands," he said, insisting that the talks marked "the beginning of the end," for Assad.