World diplomats seeking an end to Syria's war will meet again in "approximately one month" to review progress towards a ceasefire and the start of a political process, said an official statement Saturday.

The 17 countries, European Union, United States and Arab League meeting in Vienna agreed on a set calendar for a transition government in Syria within six months and elections in 18 months, however the tricky subject of the fate of Syrian President Bashar al-Assad remained undecided.