Iranian President Mahmoud Ahmadinejad announced a day of mourning and compared Chavez to a saint, saying he will "return on resurrection day."
Ahmadinejad said he has "no doubt Chavez will return to Earth together with Jesus and the perfect" Imam Mahdi, the most revered figure of Shiite Muslims, and help "establish peace, justice and kindness" in the world. The Iranian leader said he believes something "suspicious" caused the cancer that killed Chavez.
In Cuba, President Raul Castro's government declared two days of national mourning and ordered flags to fly at half-staff.
"It is with deep and excruciating sorrow that our people and the revolutionary government have learned of President Hugo Rafael Chavez Frias' decease," it said in a statement read on the nightly state TV newscast. "The Cuban people view him as one of their most outstanding sons."
Some islanders worried about the loss of the country's No. 1 ally, who has sent billions of dollars of oil to Cuba at preferential terms.
"It's a very tough blow. ... Now I wonder, what is to become of us?" said Maite Sierra, a 72-year-old Havana resident.
Across Latin American, grief-stricken supporters lit candles, waved Venezuelan flags or brandished portraits of the late leader in solidarity with mourners in Venezuela.
In Moscow, candles, flowers, and a traditional Russian bottle of vodka were left outside Venezuela's embassy. Russian President Vladimir Putin called Chavez "an extraordinary and strong man who looked into the future and always aimed high," while Prime Minister Dmitry Medvedev posted photographs of himself with Chavez to his Facebook page.
Chinese President Hu Jintao, who steps down this month, and his replacement, Xi Jinping, also sent their condolences to Vice President Nicolas Maduro, the interim Venezuelan president ahead of new elections.