Hugo Chavez's top aides accused the opposition and the media on Thursday of using the Venezuelan president's poor health to wage a "psychological war" to destabilize the country, as the cancer-stricken leader struggles with a severe lung infection.

The stance was adopted after Venezuelan Vice-President Nicolas Maduro returned from Cuba where he visited Chavez, who is suffering from complications more than three weeks after undergoing cancer surgery.

Information Minister Ernesto Villegas said Chavez developed a "severe pulmonary infection" after the surgery led to a respiratory insufficiency, requiring strict adherence to his treatment.