Syria's humanitarian crisis - in 60 seconds
16 December 2013 Last updated at 13:15 GMT
Syria's 33-month conflict has ravaged the country. The UN estimates nearly three-quarters of the country's 22 million population will need humanitarian aid in 2014.
Many Syrians trapped in besieged towns have had little help for months. Bread prices have rocketed and starvation is a major concern.
The BBC outlines the country's humanitarian crisis in 60 seconds.
Video produced by Michael Hirst