Madaya, along with neighboring Zabadani, is besieged by pro-government forces including the Lebanese militia group Hezbollah. The aid shipment there was being coordinated with a similar delivery to the northern Syrian towns of Fouaa and Kfarya in Idlib Province, which are surrounded by Syrian insurgent groups.

For months, aid to both areas has been the subject of delicate negotiations toward an agreement known as the four-towns pact. Under the agreement, some aid was delivered in October, and last month, several hundred wounded fighters and their families were evacuated from both sides.