Venezuela's President Hugo Chavez is conscious but in a "delicate and complex situation" after a cancer operation in Cuba, his deputy says, according to BBC.

Vice-President Nicolas Maduro said he had seen the president twice in the past two days.

The 58-year-old president has been in power since 1999 and was elected for a fourth term in office in October.

He is due to be sworn in for a new term on 10 January, but it is unclear if he will be able to attend ceremony.

But Mr Maduro angrily denounced speculation the president's health was failing.

Earlier, Venezuelan cabinet ministers prayed for Mr Chavez's recovery during a Mass at the presidential palace in Caracas.

Official New Year celebrations were called off after Mr Maduro announced the president had suffered new complications.

Rumours denounced

Speaking in Havana, Mr Maduro said he had visited Mr Chavez in hospital twice since arriving on Saturday.

"We have faith in God and in the doctors that Hugo Chavez will continue to make progress and sooner or later will emerge from this complex and delicate post-operative state he is in," he told the Latin American satellite network Telesur.

But he gave very little further concrete information about the condition of the president, who underwent his operation on 11 December.

He said Mr Chavez gripped his hand "with enormous strength" as they spoke, discussing political matters, the economy in Venezuela and the swearing-in of new governors following regional elections.

He denounced what he called right-wing media rumours about Mr Chavez's health as the work of "mentally ill" people, saying they were inventing and manipulating information without respect for Mr Chavez or his family.

Earlier this year, the president said he had been cleared of a cancer diagnosed in 2011 and was fit to serve out his six-year term.

But on 11 December, he went through his fourth cancer operation in Cuba.

There are also many questions about what will happen on 10 January when Mr Chavez is due to be re-inaugurated, says the BBC's Sarah Rainsford in Havana, adding that it is now three weeks since Mr Chavez has been seen or heard from.

National Assembly head Diosdado Cabello recently said that the swearing-in ceremony would be delayed in the case of Mr Chavez's absence.

But the opposition says such move would be unconstitutional.

The Venezuelan constitutions states that a new election should be called in 30 days should the president not be fit enough to attend his inauguration, the opposition argues.