Venezuelan President Hugo Chavez is “battling for his health, for his life”, according to Vice-President Nicolas Maduro.
“Our commander is sick because he gave his life for those who don’t have anything,” he said on Venezuelan TV.
Mr Chavez has not been seen in public since travelling to Cuba in December for further cancer surgery.
He returned home last month and is reported to be suffering a severe respiratory infection.
Mr 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.
President Chavez 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.
Speaking in Caracas, Mr 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.
‘Lies and nastiness’
Mr Maduro, who has been named by President Chavez as his preferred successor, said the treatment was in a “complex and difficult stage”.
The government has said Mr Chavez is breathing with the help of a tracheal tube.
Mr Chavez returned from Cuba in mid-February, sending a series of celebratory tweets thanking his Cuban hosts for their help and his fellow Venezuelans for their support.
The week before, images were released of him smiling in his hospital bed during a visit from his daughters, but little has been heard of him since.
Government officials have spoken before of Mr Chavez’s “great battle” for life but Mr Maduro’s latest comment comes amid an upsurge in rumours and speculation about the president’s health.
Mr Maduro said “lies and nastiness on Twitter and Facebook” were the work of a “small and venomous minority”.
President Chavez announced in June 2011 that he had cancer and has undergone four operations since then, as well as chemotherapy and radiation therapy.