Chavez had named Maduro as his heir, but the Venezuelan opposition is sure to press for fresh elections and tensions have been mounting over government allegations that its domestic rivals are in league with its foreign foes. Shortly before Chavez's death was announced, Maduro and other top officials had accused Venezuela's enemies of somehow giving the 58-year-old leftist the cancer that eventually killed him, and two US military attaches were expelled.
Under the constitution, elections must be held within 30 days and National Assembly speaker Diosdado Cabello must take over on an interim basis, but Chavez had urged Venezuelans to vote for Maduro if he was unable to return.
Soldiers brought the Venezuelan flag down to half-staff at the Caracas military hospital, where senior figures in Chavez's 14-year-old administration gathered before the cameras of state television to break the news. "We have received the toughest and tragic information that... comandante President Hugo Chavez died today at 4:25 pm (Tuesday)," Maduro said. "Long live Chavez!" the officials shouted at the end of his announcement.
Chavez had been checked into the hospital on February 18 for a course of chemotherapy after spending two months in Cuba, where in December he had undergone his fourth round of cancer surgery since June 2011. The once ubiquitous symbol of Latin America's "anti-imperialist" left had disappeared from public view after he was flown to Cuba on December 10, an unprecedented absence from the public eye that fueled all manner of rumors.
The government sent mixed signals about the president's health for weeks, warning one day that he was battling for his life, yet insisting as recently as last weekend that he was still in charge and giving orders.
The opposition repeatedly accused the government of lying about the president's condition.
Chavez will be mourned by many of the country's poor, who revered the self-styled revolutionary for using the country's oil riches to fund popular housing, health, food and education programs. Like-minded Latin American leaders like Cuba's Raul Castro, Ecuador's Rafael Correa and Bolivia's Evo Morales lost a close friend who used his diplomatic muscle and cheap oil to shore up their rule.
Chavez died five months after winning an election, overcoming a resurgent opposition and public frustration overa rising murder rate, regular blackouts and soaring inflation. He missed his swearing-in for a new six-year term on January 10, but the Supreme Court approved an indefinite delay. A new election could offer another shot at the presidency to Henrique Capriles, the opposition leader who lost to Chavez in October.
Defense Minister Diego Molero, surrounded by top military officers, said that the armed forces would defend the constitution and respect Chavez's wishes. His death will particularly affect Cuba's communist regime, whose moribund state-run economy has relied heavily on Chavez's oil generosity.
Under Fidel Castro's mentoring, Chavez became the face of the radical left in Latin America, with regular diatribes against US "imperialism" and the forging of ties with regimes at odds with Washington in Syria, Libya and Iran. But despite tense relations with the US, Chavez continued to export one million barrels of oil per day up north. The then lieutenant colonel gate-crashed the political scene in 1992 when he led a failed coup against president Carlos Andres Perez.
After two years in prison, he decided to take power through democratic elections, winning in 1998 to become Venezuela's youngest president at age 44. Chavez survived a short-lived coup in 2002 that lasted just 47 hours after popular protests restored him to power. A 2004 attempt by the opposition to oust him in a recall referendum was defeated.