Besieged rebel fighters in a Syrian border town and families trapped in two Shiite towns in northern Syria are expected to be evacuated on Monday in the second stage of a rare, U.N.-backed deal between warring sides in Syria's war, sources close to negotiations said.

The deal will allow scores of rebel fighters who have been holed up for months in the town of Zabadani, near the Lebanese border, to have safe passage to Beirut airport to then head for their final destination of Turkey under International Committee of the Red Cross (ICRC) auspices, the sources said.

Simultaneously, around 300 families in two besieged Shiite towns in the mainly rebel-held northwestern province of Idlib will be heading in a land convoy to the Turkish border from where they will then fly to Beirut.