TOPSHOT - Venezuelan opposition leader and self declared acting president Juan Guaido gestures during meeting with workers and union leaders, in Caracas on February 14, 2019. - Venezuela's military reinforced a blockade on Thursday morning at the border with Colombia where opposition leader Juan Guaido has vowed to bring in desperately-needed humanitarian aid despite President Nicolas Maduro's vow to keep it out. (Photo by Federico PARRA / AFP)