The Venezuelan military has blocked off a key border crossing between Venezuela and Columbia ahead of a U.S.-backed effort to bring humanitarian aid into the country amid ongoing food shortages and a leadership crisis, The Associated Press reports. The Tienditas International Bridge was reportedly blocked with a “giant orange tanker, two large blue containers and makeshift fencing”—in the same place where U.S.-backed opposition leader Juan Guaido said humanitarian aid would be brought into the country. The U.S. has reportedly pledged $20 million, while Canada has pledged $53 million in aid for the country. President Nicolas Maduro—whose re-election has been widely disputed—has vowed that no humanitarian aid will enter the country because he reportedly believes it is equivalent to “a foreign intervention.” Meanwhile, hyperinflation has forced many Venezuelans to leave or go without food or medicine. Maduro has dismissed Guaido, claiming he is a puppet of the U.S., while Guaido claims Maduro's rule is not legitimate.