By Ezequiel Minaya, Wall Street Journal

CARACAS—Venezuelan President Hugo Chavez, who has been battling cancer, reasserted that he is free of the illness during a televised prayer service Sunday and added that Jesus and Cuban leader Fidel Castro are among his "doctors."

Mr. Chavez said he no longer feels sick and was recovering from "an illness that I had," state media reported. Mr. Chavez has said that he is submitting to further medical treatment as a precaution.

During the ecumenical event, a hundred well-wishers shaved their heads in support of Mr. Chavez, who has removed most of his own hair and lost weight as he undergoes chemotherapy for the undisclosed type of cancer, according to the Venezuelan News Agency.

Venezuela's opposition has demanded more medical information from Mr. Chavez, saying that the health of the head of state is of national concern and should be publicly updated by his medical team. Detractors have also criticized the flamboyant leader for continuing to govern Venezuela during his stints in Cuba seeking medical care.

On Sunday, Mr. Chavez, who has refused to identify his doctors said that "the first doctor is named Jesus of Nazareth, the highest of healers, the second is Fidel, and the third is the medical [team]," state media reported.

Mr. Chavez has said that it was Castro, a father figure and mentor to the Venezuelan president, who delivered the test results revealing a diagnosis of cancer.

Mr. Chavez says he has submitted to two rounds of chemotherapy in Havana since last month and may undergo a third in the coming days. On June 20, surgeons in Havana removed a baseball-size tumor from Chavez's pelvic region. Subsequent examinations have shown he is free of "malignant cells," according to the Venezuelan government.

During the prayer service, Mr. Chavez grew teary-eyed while recounting a previous encounter he had with a young girl named Genesis who had terminal cancer and who handed him a Venezuelan flag at an event.

Holding the gift, Mr. Chavez said Sunday that "here is the heart of Genesis, in this flag."

Chavez and his supporters have sought to quiet questions about his health and insist that he will run for, and win, another six-year term in the coming 2012 presidential election.

Many analysts say, however, that if Mr. Chavez is forced to withdraw from office a power vacuum could result, plunging Venezuela into a period of heightened instability.