Talks set for Jan 25 in Geneva are intended as the first step in a plan endorsed by the United Nations Security Council to end the war in Syria, but the recent death of a key rebel leader complicates the task of finding a deal that would satisfy the Syrian regime and its multi-sided opposition.
Another complication has arrived with the siege by government forces of the town of Madaya and nearby villages, with accusations from all directions about whether the regime or rebels are to blame for the resulting starvation and humanitarian crisis.
The regime claimed responsibility for the death of Zahran Alloush, the commander of Jaish al-Islam (Army of Islam), who was seen as a figure with enough stature to bring about some cohesion in the demands of rival rebel groups.
Syria's war erupted in 2011 with anti-government protests and has descended into a complex civil war.
The fate of Syrian President Bashar al-Assad remains the key sticking point on all sides of the conflict. Jaish al-Islam has remained steadfast in opposition to al-Assad and to the Islamic State jihadist group. The rebels and allies in the West, including Turkey, say al-Assad must leave office. Moscow and Tehran support elections in which he could stand.
The war has killed some 250,000 people, and has displaced tens of millions.
Date written/update: 2015-12-28