Brazilian soldiers unload humanitarian aid from a Brazilian Air Force plane shortly after landing at Ala 7 air base in Boa Vista, Roraima state, Brazil in the border with Venezuela, on February 22, 2019. - President Nicolas Maduro ordered the closure of Venezuela's border with Brazil on Thursday in an increasingly fraught power struggle with Juan Guaido, the opposition leader spearheading efforts to bring humanitarian aid into the country despite a military blockade. (Photo by Nelson Almeida / AFP)