President Hugo Chavez's supporters joyfully brandished the first photos of him to appear since he underwent cancer surgery two months ago, while opposition activists said the images were worrying evidence of Venezuela's political vacuum.

In a first proof of life since Chavez's six-hour operation in Cuba on Dec 11, authorities published four photos on Friday showing him lying in a hospital bed smiling next to his daughters.

Venezuelan Vice-President Nicolas Maduro holds up a copy of a picture of President Hugo Chavez while speaking to supporters at a market in Caracas on Saturday. Miraflores Palace via Reuters

An accompanying statement, however, revealed that the 58-year-old leader was breathing through a tracheal tube and could not speak. Within hours, the photos were on sale in Caracas streets, where some of Chavez's supporters clutched them to their hearts as if they were religious icons.

"It doesn't matter that he can't talk. We understood his message," said Aniluz Serrano, 57, selling prints in colonial Bolivar Square, named for Venezuela's independence hero and Chavez's idol, Simon Bolivar.

"When I saw this photo, I thought how beautiful, here he is calling on the people to keep fighting. When I see this smile, I can see Christ, I can see Simon Bolivar." The photos and new medical details confirmed what most Venezuelans already assumed - that Chavez is seriously ill and may not be able to return to the presidency.

He has ruled the South American OPEC nation since 1999, maintaining huge popularity among the poor thanks to oil-financed welfare policies and his common touch, while alienating private business with nationalizations. Vice-President Nicolas Maduro and other allies say Chavez remains the head of state, signing decrees and giving instructions, sometimes in writing, from Havana.

"President Chavez in full recovery," was the headline of various state media. "He's alive. ... He will be back," said Idan Sotto, 24, buying one of the photos in downtown Caracas.

On Saturday, Venezuelan authorities ordered opposition politician Leopoldo Lopez and his mother to go to the prosecutor's office to face charges for "presumed irregularities" dating from 1998.

Lopez, 41, and his mother, Antonieta Mendoza de Lopez, 66, are accused of "presumed irregularities" concerning donations made by the state-run Petroleos de Venezuela to the Civil Association Justice First, a group that Lopez founded. The group became a political party in 2000.

Both have been ordered to appear at the prosecutor's office to be charged, the prosecution said in a statement, without detailing the charges.

Lopez, a charismatic politician with a winning smile, has led the center-right Popular Will Party since 2009.

In 2005, the office of the Comptroller General accused him of corruption and banned him from politics until 2014 for allegedly receiving illegal money from PDVSA and swindling money when he was mayor of the wealthy Caracas neighborhood of Cachao.

The cases were never brought to trial, and the Inter-American Court of Human Rights in Costa Rica declared the Venezuelan ruling invalid.

Lopez was a top contender to run as the candidate for the unified opposition in the 2012 presidential election, but bowed out in favor of Henrique Capriles, who shares Lopez's telenovela-star looks. Chavez defeated Capriles in the October presidential election.

The National Assembly, controlled by Chavez loyalists, opened a corruption probe on Feb 6 into two members of the Capriles' Justice First Party, accusing them of illegally accepting campaign donations without reporting them.

The move against Lopez appears to be part of a concerted government campaign against the opposition. On state TV on Saturday, Maduro accused government critics in the "corrupt right" and "parasitic bourgeoisie" of plotting "a silent coup".

Maduro had earlier said that Capriles and another opposition leader, Gerardo Blyde, would be responsible for "any act of violence" in an ongoing student protest outside the Cuban embassy decrying the influence of Havana's government in Venezuela.

Reuters-AFP