Millions of people in Syria are largely cut off from the outside world and desperate for food and aid.
In the Syrian town of Madaya, only four aid convoys have been allowed into the town over the past seven months.
ABC News is in contact with a family that is trapped in the town and we will be detailing the conditions they're working to survive on our live blog here.
Some international humanitarian organizations have been allowed access to Madaya and the other besieged towns.
Here is a list of organizations helping bring aid to residents in those towns.
This organization is an branch of the United Nations and, as their name suggests, focuses on food needs for those in crisis areas.
The United Nations Office for the Coordination of Humanitarian Affairs is helping organize relief efforts in Syria.
This U.N. program is dedicated to the needs of children and education efforts.
The United Nation's High Commission for Refugees focuses their efforts on the needs of refugees and internally displaced, many of whom are in besieged areas.
The international branch of the Red Cross ensures humanitarian protection and assistance in conflict zones.