Venezuelan President Hugo Chavez is aware that his condition is complicated following a fourth cancer operation in Cuba, Vice President Nicolas Maduro has said.

Mr Maduro is to return to Venezuela after spending several days alongside Mr Chavez and members of the President's family.

That may help end rumours that his visit was a sign that Mr Chavez was near death.

"During these days I was able to see him twice and speak with him," Mr Maduro said during an interview from Havana.

"He is completely conscious of the complexity of his post-operative state and he expressly asked us keep the people informed."

The Vice President, who has been designated as successor to Mr Chavez, said the President had grasped his hand "with immense strength" as they spoke, and asked him about the state of the economy and the swearing-in of newly elected governors.

Mr Chavez suffered unexpected bleeding as result of a complex, six-hour operation on 11 December, and later had to fight off a respiratory infection.

Mr Maduro said on Sunday that the 58-year-old leader was suffering a third set of complications as a result of the respiratory problem.

Mr Chavez's son-in-law, who also serves as Science Minister, said on Monday that the President was in stable condition and urged Venezuelans to ignore rumours of his impending death.

Mr Chavez has never said what type of cancer he has.

His death or resignation due to illness would cause a political crisis in Venezuela, where his personalised brand of oil-financed socialism has made him a hero to the poor majority but a nemesis to critics who call him a dictator.

If Mr Chavez stepped down, new elections would be called within 30 days. Mr Maduro would be the ruling Socialist Party candidate.

The President’s condition is also being watched closely by Latin American countries that have benefited from his generous assistance, as well as Wall Street investors who are drawn to Venezuela's lucrative and heavily traded bonds.

He is due to be sworn in again in Venezuela on 10 January after winning re-election in October.

But Socialist Party officials have suggested the ceremony could be delayed if he is unable to return in time.

Opposition leaders say postponing it would show Mr Chavez is not fit to govern and that new elections should be held to choose his replacement.