The head of the foreign-backed Syrian opposition says the group will attend the peace talks planned for this month in Geneva only if there is a clear timeframe for President Bashar al-Assad to step down.
Ahmad Jarba, who is the president of the so-called Syrian National Coalition, made the remarks on Sunday during an Arab League emergency meeting of foreign ministers in the Egyptian capital Cairo.
He said the opposition has decided not to attend the Geneva 2 conference unless there is a successful transfer of power with a specific timeframe.
Russia and the US have been pushing to bring the Syrian government and the opposition to the negotiating table.
The Geneva 2 conference is seen as a chance to find a political solution to the Syrian crisis. The event has been delayed for months, but Moscow and Washington are now trying to fix a date for it in mid-November.
Russia and China have urged the presence of the Islamic Republic of Iran in the conference.
Russian Foreign Minister Sergey Lavrov said on October 11 that Western countries are on the right track regarding their attitude to Iran's participation in the peace talks on the Syrian issue.
On September 29, UN-Arab League Special Envoy to Syria Lakhdar Brahimi stated that it would be beneficial if Iran takes part in the Geneva 2 conference and there is the possibility of inviting the Islamic Republic.
Syria has been gripped by deadly unrest since 2011. Reports indicate that the Western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside the country.
According to the United Nations, more than 100,000 people have been killed and millions displaced in the violence.