Venezuela’s president, Nicolás Maduro, has ordered the vast border with Brazil to be closed, just days before opposition leaders plan to bring in foreign humanitarian aid he has refused to accept.

Maduro said he’s also weighing up shutting the border with Colombia. He made the announcement on state TV on Thursday, surrounded by military commanders.

Opposition leaders led by Juan Guaidó are vowing to bring in US supplies of emergency food and medicine to highlight the country’s hardships under Maduro, who has said the country doesn’t need such help.

“What the US empire is doing with its puppets is an internal provocation,” Maduro said. “They wanted to generate a great national commotion, but they didn’t achieve it.”

Under Maduro’s orders, Venezuela this week blocked air and sea travel between Venezuela and the nearby Dutch Caribbean island of Curaçao, another point where aid was being stockpiled.

A caravan of vehicles carrying Guaidó left the Venezuelan capital, Caracas, early on Thursday, heading toward the border with Colombia as part of the effort to bring in aid stored in the city of Cúcuta starting on Saturday.

Maduro denies a humanitarian crisis, accusing the United States of leading a coup to remove him from power and using the “show” of supposed humanitarian aid as military intervention.

The socialist president is under a mounting challenge by Guaidó, who has declared himself acting president on the grounds that Maduro’s re-election was invalid.

Guaidó is recognised as Venezuela’s legitimate interim president by more than 50 governments – including the US, UK, Spain, France and Germany, while Maduro is supported by Russia, China, Cuba, Turkey and many other countries.

Guaidó’s spokesman, Edward Rodriguez, confirmed that the opposition leader, who heads the congress, was among passengers in a caravan consisting of several vehicles and buses.

Opposition leaders said they also plan to bring emergency supplies of food and medicine from Curaçao and across the jungle-covered border with Brazil.