Opposition at loggerheads over interim government

But its credibility wasn't helped by the 12 candidates who are running, including a Dubai property speculator and an IT manager who recently moved from Texas to Turkey.

Some warn setting up such a government could close the door to negotiating an end to Syria's civil war and instead harden battle lines even more.

Another obstacle is asserting the authority of any government picked by the largely exiled opposition, especially in areas where Islamist militias dominate.

Syrian opposition coalition leader Mouaz al-Khatib has said that he opposes the formation of a rival government, fearing that it would deepen divisions in Syria.

The formation of the interim government was put off twice over such disagreements, but coalition members voted last month to go ahead with the election.

And even the US has been cool to the idea of a rival government in rebel-held areas.

Last week, US Secretary of State John Kerry said that only a transitional government accepted by both the opposition and Mr Assad's government can allow Syrians to determine their future.

Issam Khalil, an MP from President Assad's ruling Ba'ath Party, said that the opposition is pursuing foreign interests and is trying to "implode Syria from the inside. Those meeting in Istanbul want to intensify the conflict in Syria, not end it," he warned.