Analysts at the Eurasia Group consultancy noted that while worldwide recognition of Guaido as interim president cemented his position as the main opposition leader, his failure to win over the military meant Maduro's fall "does not appear imminent".
Backed by Venezuela's military, Mr Maduro has refused to show any hint he is ready to cede power, setting up a potentially explosive struggle.
In Washington, Secretary of State Mike Pompeo kept up the pressure on the leftist leader, as the United States called for an emergency UN Security Council meeting on the crisis.
United Nations chief Antonio Guterres on Thursday appealed for dialogue to stop Venezuela's political crisis spiraling out of control, after Guaido declared himself interim president. Three people were shot dead on Tuesday night in southern Bolivar City during a looting of a grocery store that followed a nearby protest, Bolivar state Gov. Justo Noguera said in a telephone interview.
US diplomats in Venezuela are caught in the midst of an ongoing power struggle, and with the Trump administration siding with the opposition, their security remains uncertain.
Several former military leaders who remain in close contact with active troops said that for Guaido to even have a chance of winning over support from sectors of the military, he'd have to continue to galvanize the public and prove to skeptical military officers with much to lose that his promise of granting amnesty to those who promote change is honest. President Donald Trump promised to use the "full weight" of USA economic and diplomatic power to push for the restoration of Venezuela's democracy.
Maduro was inaugurated on January 10 to another term in office following a widely boycotted election a year ago that many foreign governments described as a fraudulent.
Meanwhile, Turkey joined Russian Federation and several other countries which came out in support of Maduro, with presidential spokesman Ibrahim Kalin writing on Twitter that Erdogan told Maduro Turkey would support him.
In a video addressing the military earlier this week, Guiado said the constitution requires them to disavow Maduro after his May 2018 re-election, which was widely condemned by the worldwide community because his main opponents were banned from running. Moscow will insist on compliance with worldwide law, Russia's RIA news agency cited Russian Foreign Minister Sergei Lavrov as saying on Friday.
However Mr Guaido has urged all foreign embassies in the country to disobey Mr Maduro's orders and not remove their diplomats. Maduro visited Moscow in December, seeking Russia's political and financial support.
U.S. President Donald Trump recognized Guaido as the interim head of state moments after his declaration in Caracas, describing Maduro's leadership as "illegitimate".
Venezuela and its state-owned oil company, PDVSA, are estimated to owe $7 billion on a combined trade debt of about $60 billion.
Many Venezuelans are awaiting Guaido's guidance on the often-beleaguered opposition's next steps.
Guaido greets supporters after taking an oath to be Venezuela's interim president.
Thousands of Venezuelans took to the streets earlier this week to force President Nicolás Maduro-who much of the worldwide community believes to have rigged the most recent election-out of office.
The latest events cap an especially tumultuous week for the troubled South American nation. On Monday, a few dozen national guardsmen seized a stockpile of assault rifles in a pre-dawn uprising that was quickly quashed.