Venezuela's President Nicolas Maduro takes part in a video conference with members of the military in Caracas, Venezuela February 21, 2019.

President Nicolas Maduro has announced the closure of Venezuela's border crossings with Brazil, as part of a sustained bid to prevent tens of millions of dollars in humanitarian aid flowing into the country.

Political tensions in Venezuela are reaching boiling point, with the poverty-stricken nation in the midst of the Western Hemisphere's worst humanitarian crisis in recent memory.

Speaking in a televised address from the country's largest military base in Caracas on Thursday, Maduro said the border with Brazil would be "completely and absolutely" closed until further notice.

The embattled socialist leader also said Thursday he would consider an imminent shutdown of the country's border with Colombia.

"It is better to prevent than regret," Maduro said.

The move comes less than 48 hours before an opposition-led plan to deliver aid from collection points in neighboring countries.

Brazil's government, which recognizes opposition leader Juan Guaido as Venezuela's rightful interim president, had pledged to assist with a delivery effort over the weekend.