At some point after that, Abrams said, US officials had been led to believe that the chief judge of Venezuela's Supreme Court, the defense minister and the chief of the presidential guard would declare their support for the constitution and, by extension, renounce Maduro's leadership.
In an hour-long address to the nation on Tuesday night, Maduro accused opposition leader Juan Guaidó and his political mentor Leopoldo López of seeking to spark an armed confrontation that might be used as a pretext for a foreign military intervention.
Venezula's military bases, airfields and ports also make it an ideal staging-post for Russian forces in the region.
Chile's foreign minister said later Tuesday that Lopez and his family had entered Chile's diplomatic residence.
Guaido is recognized as the country's legitimate president by the USA and more than 50 other nations.
"This is a movement led by Venezuelans", he said. Brazilian media put that number at 25.
Protesters yesterday clashed with the armed forces, who showed little signs of defecting from Maduro to the opposition.
"He's a figure that we have always followed", Eduardo said on Tuesday, retreating from one protest just south of Caracas' Altamira plaza where soldiers were firing tear gas at the crowd. Rioters later blocked the highway with a bus and set it on fire.
A pall of black smoke also rose from an area near a helicopter hangar on the base.
Elsewhere, human rights NGO Provea denounced the death of a demonstrator in northern Aragua state. The US-backed politician also called on the military to "keep advancing" in its efforts to oust Maduro from office.
"Venezuelan people deserve a better future, they have suffered enough and the Maduro regime must end", a spokesman for Prime Minister Theresa May said. "People of Venezuela, it is necessary that we all go out into the streets, to support democracy and recover our liberty". I think Secretary Pompeo will be addressing his counterpart.
An emergency order issued by the Federal Aviation Administration (FAA) forbids planes from flying below 26,000ft in Venezuela's airspace which rules out take-offs and landings.
Guaido has called for "the largest march in Venezuela's history" on Wednesday, May 1.
Internet observatory NetBlocks reported "multiple internet services" were restricted in Venezuela following Guaido's appeal.
The Lima Group of mostly Latin American countries announced an emergency meeting in Lima on Friday to discuss the crisis. Violent protests were particularly focused in traditional opposition strongholds of eastern Caracas, including outside La Carlota airbase.
Guaido invoked the constitution to declare himself interim president in January after calling Maduro's leadership illegitimate because of election fraud.
Lopez was convicted of having incited protests against Maduro and sentenced to 14 years in prison.