As the UN Security Council debates renewing an aid operation in Syria that serves as a lifeline for millions in the country's embattled Idlib region, relief agencies are scrambling to prepare for what they describe as a humanitarian nightmare in which there is no feasible contingency plan. 

The 15-member council has until July 10 to reauthorize a resolution that allows for the delivery of urgently needed food, medicine and basic goods that are trucked across the Bab al-Hawa crossing on the Syrian-Turkish border each month. 

The United States is calling for the cross-border operations in northwest Syria to be renewed for another 12 months, but Russia, Syria’s veto-wielding backer on the council, has signaled it will block the effort. 

The UN is tasked not only with supplying aid, but coordinating humanitarian operations among local and international nongovernmental organizations. The highly choreographed system of procurement, packaging, monitoring and transport would be virtually impossible to replicate if the resolution is not reauthorized, aid workers say.