Venezuelan President Hugo Chavez is in Cuba for medical treatment.

Caracas - Top Venezuelan officials gathered in Cuba on Thursday amid growing demands for news about cancer-stricken President Hugo Chavez' condition, days before he is to be sworn in for another term.

The latest senior official reported to have arrived in Havana

was Disodado Cabello, who as head of the National Assembly would be a key player in any succession plan should Chavez be unable to take the oath on January 10.

Ultimas Noticias, a newspaper that has generally been well connected to the government, said Cabello flew to Cuba on Wednesday to join Chavez's handpicked successor Vice President Nicolas Maduro and other top officials.

Chavez is in Cuba, Venezuela's close ally among leftist-led Latin American nations, for medical treatment.

Among his visitors have been son-in-law Science and Culture Minister Jorge Arreaza; Attorney General Cilia Flores, who is Maduro's partner; and Chavez's brother Barinas governor Adan Chavez.

The Venezuelan president has not been seen since he underwent a long and complicated surgery for a recurrence of cancer 23 days ago, and officials have acknowledged that his recovery has been difficult.

On Wednesday, Bolivia's President Evo Morales, a close Chavez friend and ally, said he had spoken to his family and that his condition was “very worrying.”

“Let's hope our prayers will be effective in saving the life of brother President Chavez,” Morales said of Chavez, the longtime leader of OPEC member Venezuela, which has the world's largest proven oil reserves.

Chavez, who was re-elected October 7 despite a long, debilitating battle with cancer and the strongest opposition challenge yet to his 14 year rule, is supposed to take office in a week for another six year term.

But it was still unclear whether he would be fit to take office.

Venezuela's constitution calls for new elections to be held within 30 days if the president is unable to take the oath of office or dies during his first four years in office.

Former vice president Elias Jaua said in a tweet Wednesday that Chavez alone “will decide what to do January 10,” suggesting he had no plans for now to give up the presidency.

On the other hand, Assembly speaker Cabello tweeted that “we Chavistas are very clear on what we will do.”

Before leaving for Cuba for his fourth round of surgery, Chavez chose Maduro as his successor and left him in charge of the country without formally handing over the powers of the presidency.

Rumors meanwhile have proliferated in the absence of detailed information about Chavez's health, and the main opposition movement had demanded the government to “tell the truth” about his condition.

“It is essential that the government act in a manner that gives confidence. It is essential that it tell the truth,” said Ramon Guillermo Aveledo, head of the opposition umbrella group MUD.

He called on the government to provide “a diagnosis and a medical prognosis” on the 58-year-old Chavez's condition.

Calls for greater accountability to the public also went out on social networks.

“Venezuelans demand that #YouTellTheTruthAboutChavez the country does not depend on 1 man but on the will of 26 million,” wrote (at)Aurimar_Espina on Twitter.

The government has not identified even the type of cancer affecting Chavez nor its prognosis, since the disease was first detected by Cuban doctors in June 2011.

Information about his progress has come in vague, often upbeat comments by Maduro and a handful of other aides and close allies like Bolivia's president.

In an update Wednesday, Chavez's son-in-law Jorge Arreaza, the country's minister of science and technology, said in a tweet that the president's condition was “stable” but still delicate.

Morales told reporters in Bolivia on Wednesday that he had spoken with the Venezuelan leader's family, and that “our brother President Chavez's situation is very worrying.”

“It is very painful for me,” the Bolivian leader acknowledged.

In Brazil, an official at the Planalto presidential palace said Brasilia was following Chavez's situation “with concern.”

But the official, who spoke on condition of anonymity, said there was “no reason to be concerned, to believe, that something extraordinary could happen in the future with Venezuela.”

Maduro said in a television interview from Havana on Tuesday that Chavez was conscious and fully aware “of how complex the postoperative condition is.”

“At times there have been slight improvements, at times there have been stationary situations,” he said. - Sapa-AFP