Damascus, January 14 (RHC)-- An international peace conference for Syria is set to begin next week in Geneva. But the summit remains in doubt as Syrian opposition groups have yet to confirm their attendance.

The main exile group, the so-called Syrian National Coalition, has postponed a vote until later this week amid continued internal disputes. The United Nations and Russia have both called for an Iranian role in the talks, but the Barack Obama administration continues to claim Tehran would not be taking part.

The uncertainty surrounding the Geneva talks comes amidst continued violence between rebels in northern Syria. Activists say the al Qaeda-linked Islamic State of Iraq and the Levant has executed up to 100 fighters from another al-Qaeda group, the Nusra Front, over the last several days.