Opponents to Venezuela's President Nicolas Maduro confront loyalist Bolivarian National Guard troops firing tear gas at them, outside La Carlota military airbase in Caracas, Venezuela, Tuesday, April 30, 2019. Venezuelan opposition leader Juan Guaidó took to the streets with activist Leopoldo Lopez and a small contingent of heavily armed troops early Tuesday in a bold and risky call for the military to rise up and oust socialist leader Nicolas Maduro. (AP Photo/Fernando Llano)