Military officers still loyal to Mr Maduro have used a truck tanker and huge shipping container to block access to the Tienditas bridge which links Colombia and Venezuela at the key border town of Cucuta. Emergency supplies including medicines and high-protein foods are arriving in Cucuta this week at the request of Venezuelan opposition leader and self-declared interim president Juan Guaido But Mr Maduro is taking a defiant stance in the face of this latest challenge to his weakening authority.
He said: “We are not beggars. You want to humiliate Venezuela, and I will not let our people be humiliated.
“Nothing will enter, not one invading soldier.”
His hardline position is at odds with poverty-stricken Venezuelans when have been hit hardest by the country’s economic collapse.
Ticket tout Miguel Angel said: “Maduro has said he won’t let it through but he needs to. Everyone there is hungry.”
The US could attempt to seek the approval of the United Nations Security Council to deliver aid without Mr Maduro’s co-operation but Russia would probably block such a move.
Jeremy Konyndyk, a senior fellow at the Centre for Global Development, said Mr Maduro’s continuing control of Venezuela’s military and all the territory meant getting aid across the border will be difficult but warned against politicising the assistance.
He said: “The more it looks like an overt attack on the authority of Maduro, that makes the aid more of a target.”
A US official said the aid will be kept at the main Colombian-Venezuelan border crossing at Cucuta with more supplies being prepared in Brazil and in the Caribbean.
He said: ”I anticipate having perhaps a dozen locations all around Venezuela where such aid will be staged.”
Opposition politician Miguel Pizarro said Mr Guaido’s team would talk about how the aid would move once it was in place.
Shipments aree also coming from Venezuelan companies abroad, Colombia, Canada and Germany.
A senior US administration official said it was up to Mr Guaido to decide when and how to move the supplies into the country.
He said: ”We will seek to help him to do so by whatever means possible.”
Prepositioning aid in warehouses or in truck convoys at border posts for weeks, or sometimes months, is common while officials negotiate safe passage.
Pressure is growing on Mr Maduro to step down after more than a dozen EU countries joined the US, Canada and a group of Latin American countries in recognising Mr Guaido as Venezuela’s legitimate leader.
Russia, China and Turkey still back socialist Mr Maduro and have accused Western nations of meddling in Venezuela’s internal affairs.