Venezuelan Vice President Nicolas Maduro is to deliver the annual state of the nation address to lawmakers on Tuesday in place of cancer-stricken President Hugo Chavez, who is convalescing in Cuba.

Maduro, Chavez's chosen political heir, will give the speech in accordance with the constitution, due to Chavez's authorized leave of absence, the first vice president of the National Assembly, Dario Vivas, told Venezuelan radio.

Mixed signals from officials in Venezuela sparked confusion on Monday over the condition of cancer-stricken President Hugo Chavez, under treatment in a Cuban hospital for over a month.

Chavez is "fighting for his life," former vice president Elias Jaua said.

Cuban President Raul Castro on Saturday voiced his support for the Venezuelan government, as its cancer-stricken leader Hugo Chavez convalesces in Havana, with no sign of when or if he might return home.

Castro made the comments during a meeting with Venezuelan Vice President Nicolas Maduro, who arrived in the Cuban capital late Friday to check on his ailing boss, who had a difficult fourth round of cancer surgery last month.

With President Hugo Chavez ailing and absent, Venezuela's leftist government launches a new presidential term Thursday with a display of popular support on the day he was to be inaugurated.

Leaders of other leftist Latin American government also began arriving in Caracas to pay tribute to Chavez, 58, who has not be seen in public since he underwent cancer surgery a month ago in Havana.

Venezuela heads into uncharted political waters Wednesday without ailing President Hugo Chavez amid calls for the Supreme Court to decide if his government's postponing his inauguration is constitutional.

After days of suspense, the government confirmed Tuesday that Chavez, recovering in Cuba from cancer surgery, was still too sick to return for his re-inauguration Thursday and would take the oath of office at a later date before the Supreme Court.

The United States Tuesday wished Venezuelan President Hugo Chavez a speedy recovery as he battles cancer in a hospital in Cuba, just two days before he is due to be sworn in for a new term.

"Obviously we are, as we would be for anybody suffering what he is suffering, concerned for his health, and wishing a speedy recovery," State Department spokeswoman Victoria Nuland said.

Venezuela's top opposition leader on Tuesday urged the Supreme Court to rule on whether cancer-stricken President Hugo Chavez's re-inauguration can be postponed, as his government argues.

"I do not know what the judges of the Supreme Court are waiting for. Right now in Venezuela, without any doubt whatsoever, a constitutional conflict has arisen," Henrique Capriles said.

A constitutional fight over cancer-stricken President Hugo Chavez's status intensified Tuesday with the government planning a massive show of support in the streets on the day he is supposed to be sworn in to a new term.

The country's main opposition coalition, meanwhile, turned to international organizations for support, warning the Organization of American States of an "alteration of the constitutional order" if Chavez is unable to take the oath of office as scheduled on Thursday and his government remains in charge anyway.

Venezuelan leader Hugo Chavez's allies staged a show of unity on Saturday, re-electing the ruling party's Diosdado Cabello as parliamentary speaker, while their president battles cancer in Cuba.

The closing of ranks by the United Socialist Party of Venezuela (PSUV) came as it emerged as all but certain that illness will keep Chavez from being sworn in to a new six year term on January 10 as scheduled.

Venezuelan emergency workers launched a sea and air search Saturday after a small plane carrying the head of Italy's Missoni fashion family disappeared over coastal islands, officials said.

The plane carrying Vittorio Missoni -- 58-year-old son of the eponymous fashion label's founder Ottavio Missoni -- and his wife Maurizia Castiglioni, another couple and two Venezuelan crew members went missing after taking off from the Los Roques resort late Friday, the Venezuelan Interior Ministry said.