London: Venezuelan President Hugo Chavez is "battling for his life", his deputy Nicolas Maduro said on state TV.
"Our commander is sick because he gave his life for those who don`t have anything," the BBC quoted Maduro as saying.
Chavez has not been seen in public since he had cancer surgery in Cuba in December and is reported to have a severe respiratory infection.
The government earlier said that Chavez, now back in Venezuela, is running the country from the hospital.
Chavez, who has been in office for 14 years, is believed to have cancer in his pelvic area but his exact illness has never been disclosed.
He was re-elected for another six-year term in October 2012, but the Supreme Court ruled that his swearing-in could be delayed because of his illness.
Maduro said the president "didn`t take care of his health because he gave his body and soul" to the people.
"He`s battling for his life, for his health, and we are there with him," he said.
Maduro, named by Chavez as his preferred successor, said the treatment was in a "complex and difficult stage".
The government has said that Chavez, breathing with the help of a tracheal tube, is writing orders and meeting ministers from his sickbed at a military hospital in Caracas.
Chavez returned from Cuba in February, and sent a series of celebratory tweets thanking his Cuban hosts for their help and his fellow Venezuelans for their support.
Though photos have been released of him smiling in his hospital bed during a visit from his daughters, little has been heard of him.
Government officials have spoken before of Chavez`s "great battle" for life but Maduro`s comment comes amid an upsurge in rumours and speculation about the president`s health.
Maduro said "lies and nastiness on Twitter and Facebook" were the work of a "small and venomous minority".