Syria's opposition will consult with backers Saudi Arabia, Qatar and Turkey before it decides whether to take part in a peace conference proposed by the United States and Russia, its acting chief said Monday.
"It is too early to decide whether or not we will take part, because the circumstances of this conference are not yet clear. There is no agenda or calendar yet," said the opposition National Coalition's acting head George Sabra.
"The list of participating states and their representatives has not yet been announced," Sabra told reporters in Istanbul.
"We are still holding consultations with revolutionary forces inside (Syria), and with our friends and allies in the region -- Turkey, Saudi Arabia, Qatar and other Arab countries -- to take the appropriate decision," he added.
Riyadh, Ankara and Doha are the Syrian opposition's main backers. They provide it with money and light and medium weapons.
The Coalition had said Sunday it will discuss on 23 May the US-Russian proposed conference, that aims to reach a political solution for a conflict that has left more than 80,000 dead in just over two years.
Last week, US Secretary of State John Kerry visited Moscow and the two countries agreed to push rebels and the regime of President Bashar al-Assad to build on a deal agreed last year in Geneva and to enter into talks.
But Sabra said on Sunday that the opposition demands Assad's departure as part of any resolution to the conflict.
"We have conditions for all political initiatives... chiefly the cessation of violence and Bashar al-Assad and his clique's unconditional departure," he said.
Sabra meanwhile accused Assad's regime of being behind a twin bombing that left 46 people dead in Turkey on Saturday.
"The regime will be punished by fighters of the (rebel) Free Syrian Army for what it did in Reyhanli," he warned.