(Adds quotes, background)
By Roberta Rampton
WASHINGTON, May 6 (Reuters) - U.S. Vice President Mike Pence is set on Tuesday to offer new incentives to Venezuela's military to turn against President Nicolas Maduro, responding to an attempted uprising that fizzled out last week, a senior administration official told Reuters.
In a speech to the Americas Society at the State Department, scheduled for 3:25 p.m. (1925 GMT), Pence will also warn that the United States will soon move to sanction 25 additional magistrates on Venezuela's supreme court, the official said on Monday, speaking on condition of anonymity.
Pence will also offer assistance for refugees who have fled the country, and an economic aid package contingent on a political transition, according to the official.
Pence's speech will be the first look at the Trump administration's recalibrated strategy following massive street protests last week led by Juan Guaido, the opposition leader backed by the United States and most other Western countries.
Guaido had described the protests as the start of his "final phase" to oust Maduro, but mass military defections failed to come to fruition.
President Donald Trump has invested considerable political capital in the diplomatic and economic intervention in the Venezuela crisis.
Although Guaido's attempted uprising failed to immediately dislodge Maduro, it exposed new fissures within the country, the official said.
"A week before last, all the media - including you guys, everybody - was writing about how there's no way forward, complete stalemate," the official said.
"Suddenly last week, everyone woke up."
NEW CARROTS, AND A STICK
Guaido, the president of the country's national assembly, invoked Venezuela's constitution in January to declare himself interim president of the country, arguing that Maduro's 2018 re-election was illegitimate.
Maduro - who has said Guaido is a puppet of Washington - has sought to show that the military remains on his side, but opposition leaders and U.S. officials have said that support is tenuous.
"They sat back in the barracks and they're there, but they don't want to be identified as the institutional source of repression," the official said.
Pence will offer new "carrots" to the Venezuelan military, the senior official told Reuters, declining to provide details of the incentives ahead of the speech.
"He'll be showing where the opportunities lay if people do the right thing moving forward," the official said.
Pence is also set to outline new assistance for Venezuelans who have fled the oil-rich OPEC member, which has been plagued by hyperinflation and shortages of food, water, power and medicine - and a "Day One" economic assistance plan for Venezuela contingent on Maduro's departure, the official added.
The vice president in addition will deliver a "warning shot" to magistrates on Venezuela's supreme court. The Treasury Department sanctioned the court's president, Maikel Moreno, in 2017 and the seven principal members of its constitutional chamber - and is now preparing to sanction the 25 remaining members of the court, the official said.
"We feel like that's where the pressure needs to be," according to the official.
"All 32 magistrates in the TSJ are going to sink or swim together," the official said, using the acronym for Tribunal Supremo de Justicia.
The court would be responsible for signing off on any warrant for an arrest of Guaido - a move the U.S. official emphasized would have severe consequences.
The United States imposed sweeping sanctions on Venezuela's state-owned oil company, PDVSA, in January. Oil provides 90 percent of export revenue for Venezuela.
The administration also continues to work on other responses to increase financial pressure on Maduro, including "secondary sanctions" on companies from other countries that do business with Venezuela, and additional shipping sanctions for oil, the official said. (Reporting by Roberta Rampton; Editing by Peter Cooney)
Our Standards: The Thomson Reuters Trust Principles.