Venezuela's President Hugo Chavez suffered a respiratory infection but is "stable" again in a Cuban hospital following cancer surgery a week ago, the government said on Tuesday.
Chavez, 58, is battling to recover from a fourth operation since he was first diagnosed with the disease in mid-2011.
"The general condition of the commander-president is stable after he was diagnosed with a respiratory infection and the medical team treated him immediately," Information Minister Ernesto Villegas said in the latest update on Chavez.
"It has been controlled."
Villegas said Venezuela's socialist leader, who has ruled the South American OPEC nation for 14 years, had been ordered to take "complete rest" and follow medical instructions strictly.
"This type of infection is one of the most common consequences in patients who have undergone complicated surgery, like President Chavez did last December 11," Villegas added.
Though Venezuelan officials are upbeat about Chavez's possibility of recovery, speculation is rife that he may have to step down from power, or might not even survive.
Supporters are praying for him round-the-clock in unprecedented scenes of emotion across Venezuela.
Chavez himself raised the possibility of his incapacitation before leaving for Cuba, naming Vice President Nicolas Maduro as his preferred successor and urging Venezuelans to vote for him if there is a new presidential election.
He is due, however, to start a new term on January 10.
"The prognosis is not good," said an official in a South American government with knowledge of Chavez's health situation. He forecast Chavez would not be sworn in on January 10 and said preparations for a transition were underway in Venezuela.
The consequences are huge, not just for a nation with the world's largest crude reserves, but also for an alliance of left-wing Latin American governments led by Chavez and dependent on subsidized oil and other economic largesse from Venezuela.
The normally garrulous and spotlight-hugging Chavez has not been seen or heard from in public since a couple of days before his operation in Cuba.
A Brazilian governor said that the nation's former leader, Luiz Inacio Lula da Silva, believes Chavez's health is fragile and wants to visit his leftist friend in Havana.
"Lula is very worried about Chavez's health. He thinks the situation is delicate," Ceara Governor Cid Gomes told Reuters.
Should Chavez's presidency end, a new election would have to be called within 30 days.
That would set up a potential battle between his chosen heir, Maduro, and opposition leader Henrique Capriles.
In one indicator of how the political forces are shaping up in polarized Venezuela, Chavez allies won a commanding 20 out of 23 governorships in state elections on Sunday. Capriles, 40, held his post as governor of Miranda state, but was disappointed at the opposition's showing on a national level.
Various of the ruling Socialist Party's winning governors celebrated on Tuesday by dedicating their victories to Chavez.
"The election results clearly bode well for Nicolas Maduro's likely candidacy. Though voter turnout was low, the Socialist Party's decisive victory suggests that demand for change is neither widespread nor the dominant sentiment," political consultancy Eurasia Group said.
"Moreover, the results demonstrate that Chavistas can still clearly mobilize voter turnout even when Chavez is not on the ballot and in a context where he was largely unable to campaign for his party due to his health problems."