US sources said the İstanbul discussions will focus on a common operational focus with US ally Turkey and the Syrians in order to shape a democratic post-Bashar al-Assad period in Syria.
Coordinating support for the Syrian opposition will be a key agenda item, sources said, adding that Clinton acknowledges the Turkish concerns about the crisis happening to its southern neighbor.
During the visit, Clinton is also expected to announce an additional $5.5 million in US humanitarian aid to Syria, which will bring the total US aid to $82 million since the crisis began 17 months ago.