Raul Arboleda / AFP – Getty Images

Two men paint a mural portraying Venezuelan President Hugo Chavez with the slogan “We shall overcome” on the streets of Caracas on Jan. 8, 2013. 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.

Ailing Venezuelan president Hugo Chavez will not be able to attend the presidential swearing-in ceremony Thursday in Caracas, government sources said Tuesday.

In a statement read by National Assembly President Diosdado Cabello, Vice President Nicolás Maduro said Chavez’s medical team in Cuba indicated the president’s post-surgery recovery time needs to be extended.

Venezuela’s opposition is accusing the government of violating the constitution by proposing to delay Chavez’s inauguration for a new term.

The socialist leader’s allies say the Jan. 10 inauguration date laid out in the constitution is just a “formality.”  They say Chavez, who has not been heard from for almost a month after complex cancer surgery in Cuba, can take office when his health allows.

The dispute centers on an article of the constitution that says a president-elect should be sworn in on Jan. 10 but does not say what happens if the inauguration does not take place that date.

The official position is that Chavez is fulfilling his duties as head of state despite a severe respiratory infection that has at times left him struggling to breathe. He has not been seen in public or in a live broadcast since his surgery.

The government, which has refused to discuss having Chavez temporarily step aside as he recovers, is providing only terse statements with bare-bones details of his condition.

The Associated Press and Reuters contributed to this report.