As a shipment of US aid waits in a Colombian frontier warehouse, hungry Venezuelans living nearby are wondering when they will next eat.

“They should just start handing it out here,” said Jorge Arráiz, who lives on the streets in Cúcuta, the Colombian city that has become a way station for more than a million people fleeing his home country’s humanitarian crisis. “My children back in Venezuela can’t eat. Food is no use waiting around in storage.”

Juan Guaidó, the opposition figurehead now recognized as Venezuela’s leader by dozens of governments, announced on Tuesday that caravans of volunteers will take the shipment of food and medicine across the border on 23 February.

The move is only likely to provoke the Venezuelan government, which as Guaidó made his announcement, was parading troops on the same international bridge which the opposition has chosen as a staging area.

It is as though both sides are reading from the same script.

US officials and opposition leaders have explicitly stated that one of the goals of the aid is to weaken Nicolás Maduro, by forcing the Venezuelan military to choose between blocking the aid caravan or disobeying their boss. The tactic also allows them to paint Maduro as a callous dictator who puts pride before his own starving people.

When Venezuelan authorities positioned shipping containers and a fuel tanker across the Tienditas international bridge, opponents of Maduro – including the US secretary of state Mike Pompeo and US senator Marco Rubio – highlighted images of the improvised blockade to reinforce their message that the Venezuela president was refusing to let food in.

“By blocking aid to the Venezuelan people, Maduro is committing a crime against humanity. And military leaders in Venezuela who carry out this order are disqualifying themselves from any sanctions relief or post-Maduro US-backed guarantees,” tweeted Rubio.

Meanwhile, Maduro and his circle deny there are food shortages in Venezuela – despite widespread reports of chronic hunger in the country – and have portrayed the aid as a Trojan horse sent by the US and its allies. His vice-president, Delcy Rodríguez, even went so far as to claim the food packages had been poisoned with carcinogens.

“There is no famine in Venezuela,” Maduro said in a testy exchange with the BBC broadcast on Tuesday, adding that media coverage of food shortages were following a “script… established in the west to disfigure the Venezuela situation, and justify any intervention, any aggression, as is happening right now”.

The politicization of the aid has caused consternation among humanitarian groups, with over a dozen NGOs with offices in Colombia issuing a statement reminding relevant parties that aid should be geared towards saving lives rather than achieving political goals.

Nicolas Maduro at a rally on Tuesday. Photograph: Reuters

“We remind interested parties that any potential political use of humanitarian aid can generate risks, in particular for those the aid is intended to support, if this use is not based on technical and objective criteria,” the statement signed by War Child, Oxfam and others read. The International Red Cross had already stated it will take no part in the delivery of aid for similar reasons.

For now, the first shipment of aid sits in a warehouse next to the Tienditas bridge, which was finished in 2016 but never inaugurated. Although thousands cross the nearby Simón Bolivar bridge on foot every day, the border has been closed to most vehicles since 2015 following a string of disputes between the two countries.

So far, only a small part of the $20m in aid promised by the US has arrived; Canada has promised $40m and the UK has said it would provide £6.5m, funneled into the country via charities and other aid organisations already in Venezuela.

But analysts say that the pledges amount to a drop in the ocean compared to Venezuela’s desperate needs.

“Look, no one is going to deny that getting food and medicine to people is a good thing, but it’s so little and if it is being used for political point-scoring then it goes against a vital humanitarian principle,” said Geoff Ramsey, an analyst at the Washington Office on Latin America. “This aid has become politicised.”

For now, Guaidó and his international backers have the advantage in the propaganda war, said Dimitris Pantoulas, a Caracas-based analyst and consultant.

“The Maduro government needs a new narrative that can touch its supporters’ souls,” he said. “To deny the aid or to say that the country does not need ‘charity’ sounds awkward to many ears when you think about the hardship the majority of the population faces.”

At the Simón Bolivar bridge just outside Cúcuta, a hungry working-class Venezuelan family was preparing yesterday to take a bus to Cali, a Colombian city where they hope to start a new life.

“Maduro talks of an economic war waged against Venezuela but we are already living through war,” said Victor Peña, who was once the breadwinner but now does not make enough money to provide for his family. “When people are starving and scared to leave their houses, how is that not a war?”