CARACAS, Venezuela — Hundreds of Red Cross volunteers sifted through donated medication, hygiene kits and surgical material in warehouses across Caracas, Venezuela, on Wednesday, as aid workers began to grapple with the challenges of delivering humanitarian supplies in a violent and polarized nation where even basic transportation infrastructure has crumbled.

The launch of the large-scale humanitarian campaign by the International Federation of the Red Cross and Red Crescent Societies also raised questions about how the international community can handle a humanitarian disaster caused largely by the policies of a government intent on staying in power, rather than war or natural disaster.

“This is a pretty unique situation with no precedent in modern Latin American history,” said Tamara Taraciuk, a Venezuela expert at Human Rights Watch who this month helped write a report on the country’s humanitarian crisis. “It’s a completely man-made crisis. No one can tell you how long it will last or how much will be needed.”

The arrival of 24 tons of Red Cross supplies to Caracas airport Tuesday had been welcomed by Venezuelans and by local charities, which saw the campaign as crucial.