In this April 27, 2017 photo, a volunteer of the non-profit Accion Solidaria organizes imported medicines alphabetically, in a store room in Caracas, Venezuela. It's a thankless, routine task common to pharmacies and hospitals worldwide. But this being Venezuela, where shortages are widespread, viewing the treasure trove of sometimes hard-to-find medicines can feel almost subversive. (AP Photo/Fidel Suarez)

In a stuffy, second-floor store room, a volunteer sorts through boxes of imported medicines and arranges them one by one on metallic shelves in alphabetical order. There's Euthyrox for thyroid problems, Clexane to stop blood clots and over-the-counter painkillers like ibuprofen.

It's a thankless, routine task common to pharmacies and hospitals worldwide. But this being Venezuela, where shortages are widespread, viewing the treasure trove of sometimes hard-to-find medicines can feel almost subversive.

For months, as Venezuela's economy has gone off the rails, the United Nations, U.S. and Latin American governments have called for President Nicolas Maduro to accept to ease shortages that have helped spark a growing anti-government protest movement. The embattled socialist leader has refused, seeing foreign offers of help as a possible Trojan horse that could open the politically turbulent nation to foreign military intervention. The ban extends to the Roman Catholic Church's charity arm.

"The humanitarian corridor assumes the existence of a humanitarian crisis," Foreign Minister Delcy Rodriguez said recently. "It's a theory constructed by the Pentagon so that the U.S. can intervene."

But in piecemeal fashion, with painstaking effort and quiet diplomacy, some groups are chipping away at the blockade. They include Accion Solidaria, which began two decades ago as a small clinic and support network for HIV/AIDS patients but has become a lifeline for Venezuelans suffering from all kinds of illnesses.

Every month, the group's offices in central Caracas provide free medicine to some 700 people arriving with a doctor's prescription and looking for some of the pharmaceutical drugs the organization has collected from donors around the world. Its stockpile, posted daily online to its almost 20,000 Twitter followers, runs from neatly-packaged drugs off the assembly line to half-filled pill containers with patient's names blacked out. The group also accepts expired medicines rather than provide nothing to people in need.

"It's not just people's physical well-being and the slow deterioration of their health, but in some cases also the mental anguish and damage that this situation produces," said Feliciano Reyna, the nonprofit's founder.

In this April 27, 2017 photo, Feliciano Reyna, founder of the non-profit Accion Solidaria, speaks during a interview, in Caracas, Venezuela. Accion Solidaria, which began two decades ago as a small clinic and support network for HIV/AIDS patients, has become a lifeline for Venezuelans suffering from all kinds of illnesses. (AP Photo/Fidel Suarez)

Venezuela's government has long preferred to provide aid to other nations, not see itself as a country with deep needs of its own. It was among the biggest providers of aid to Haiti following the 2010 earthquake and in March, the same day Maduro asked the U.N. to help him improve the distribution of medicine supplies at home, it dispatched two cargo planes of emergency supplies for flooding victims in Peru.

A new bipartisan bill in the U.S. Congress would provide $10 million in humanitarian assistance to Venezuela. Opening a "humanitarian corridor" is also among the top demands of Maduro's opponents.

The Venezuelan Medical Federation estimates that hospitals lack almost 98 percent of medical supplies needed, while pharmaceutical industry representatives last year said 80 percent of prescription drugs were in short supply after most foreign drug manufacturers cut off commercial ties over more than $4 billion in unpaid debts.

Donations pour in from around the globe, but especially from South Florida, home to the largest U.S. concentration of Venezuelans. Initiatives range from grassroots groups organized over WhatsApp of people donating a few boxes of baby formula to politically-charged groups such as "Rescue Venezuela," started by the wife of jailed opposition activist Leopoldo Lopez. The largest group, Humanitarian Aid for Venezuela Program, has dispatched 450,000 pounds of donated items collected over the past three years.

More recently, as the anti-government protests in Venezuela have turned deadly, immigrants have mobilized supplies that are harder to send and difficult to find. They include gauze bandages and rubbing alcohol, as well as gas masks and walkie-talkie radios to keep protesters safe against attacks of tear gas and rubber bullets fired by security forces.

"Those outside the country feel impotent and want to help," said Jose Colina at an event where he and dozens of other exiles stuffed boxes full of first aid items.

"If we were back home we'd surely be marching," added Carolina Belfort, holding back tears.

In this May 6, 2017 photo, volunteers pack first aid items bound for Venezuela at a restaurant in Miami. In Venezuela, shortages are widespread, from food items to medicines. Many pharmaceutical drug companies stopped shipping medicines to Venezuela over the past year over billions in unpaid debts. (AP Photo/Gisela Salomon)

But getting goods into the country requires some sleight of hand.

Most shipments are transported by dubious Venezuelan-run courier services that pay off customs officials to look the other way. To draw as little attention as possible, the mostly air shipments are kept small and information on the merchandise, some of which has a high resale value on Venezuela's black market, is omitted from delivery forms. More sensitive items such as gas masks for protesters are smuggled across the border from Colombia.

Many items don't get through. One major U.S. relief organization, which requested anonymity to prevent jeopardizing its under-the-radar work in Venezuela, said it has resorted to bringing items through the diplomatic pouch of a Caribbean government aligned with Maduro after half of its shipments were confiscated the past year.

Leaders for the same group said Venezuela's refusal to allow foreign aid is not seen even in conflict zones in the Middle East and Africa where governments such as Maduro's oppose the U.S. They said if they could get the aid in they would work with Venezuelan officials to distribute it through public hospitals.

Officials with other aid agencies say the supplies they manage to bring in are a drop in the bucket compared to Venezuela's needs.

"If the Venezuelan ports were to open to relief supplies we want to be ready to send dozens of containers," said Sean Lawrence, executive director of Southern California-based relief charity Giving Children Hope, which has started sending supplies to Venezuela's neighbors in the hope they will be easier to bring in by land. "We know we have a responsibility to respond."