Syria's opposition on Friday urged President Bashar al-Assad's government to speak out on whether it will take part in an international peace conference, after Russia claimed the regime had agreed "in principle" to attend.
"We would like to hear that statement from the Assad government. This has been related to us through the Russians, I have no idea why the Syrians are silent," Louay Safi, spokesman for the National Coalition, told AFP at a meeting of the main Syrian opposition group in Istanbul.
"We need more clarity. The announcement is still very vague. And why is it not made by Damascus?"
The peace conference, dubbed "Geneva 2" and expected to be held in June, would be aimed at ending the raging Syrian civil war, which in two years has killed more than 90,000 people.
But organisers must first get both sides to attend.
The conference was jointly proposed by Russia, a key backer of Assad, and the United States, which supports the rebels fighting to overthrow him.
Earlier Friday, Russian foreign ministry spokesman Alexander Lukashevich said Moscow had "received an agreement in principle from Damascus to attend the international conference".
Meeting in Istanbul for three days, members of the opposition have stipulated that in order for the conference to go forward, the National Coalition would need international guarantees that talks would lead to Assad's resignation.
"We would like to have guarantees particularly from the Russian side, because the Russian leadership has been defending Assad himself," said Safi.
"If the Russians will come forward and realise that they are moving against history and siding with the wrong party, then I think we are going to see a meaningful change, and that will save the Syrian people, who have suffered a lot," he added.
The Coalition's meeting began Thursday, a day after backers of the anti-Assad uprising gathered in Amman and told the Syrian regime that should it fail to work for peace, they would step up their assistance to the opposition.
"As far as the United States, France and the rest of participants in Amman's conference are concerned, the framework for Geneva 2 was clear," said another Coalition member, Khaled Khoja.
"But if they are playing with words and trying to gain time, we can't consider that the Syrian regime is really willing to talk," Khoja told AFP.
He also said only if the opposition has the upper ground in battle will the regime accept to negotiate on the rebels' terms, renewing opposition calls for military aid.
"We want the Friends of Syria (who back the uprising)... to increase their military assistance to the (rebel Free Syrian Army's) command, until Assad complies to the idea of a real political solution," Khoja added.