Caracas, Venezuela (CNN) -- A day after officials announced the cancer diagnosis of Argentina's president, Venezuelan President Hugo Chavez wondered Wednesday if the United States could be infecting the region's leaders with the illness.
Five current or former Latin American presidents have battled cancer in the past few years, including Chavez himself, who claims to have beaten an unspecified cancer.
Chavez prefaced his remarks at a military event in Caracas by saying, "I don't want to make any reckless accusations," but the Venezuelan president said he was concerned by something he finds "very, very, very strange."
"Would it be strange if (the United States) had developed a technology to induce cancer, and for no one to know it?" he asked.
Chavez cited the revelation this year that the United States, between 1946 and 1948, had carried out human experiments in Guatemala where subjects were exposed to sexually transmitted diseases.
That was 50 years ago, Chavez said, and he posited: Will it be discovered 50 years from now that the United States was infecting presidents with cancer?
"I don't know. I'm just putting the thought out there," Chavez said.
Victoria Nuland, a U.S. State Department spokeswoman, told reporters Thursday that Chavez's assertion was "horrific and reprehensible."
The Venezuelan president, who has a firm anti-U.S. stance, frequently hurls accusations at his political enemies, domestic and foreign. He has repeatedly said the United States is trying to destabilize his government.
A spokesman for Argentine President Cristina Fernandez de Kirchner said Tuesday that doctors had diagnosed her with thyroid cancer. She is scheduled to undergo surgery next week.
Paraguayan President Fernando Lugo was diagnosed with non-Hodgkin's lymphoma in 2010.
Brazilian President Dilma Rousseff overcame cancer while she was a candidate for the office, and former Brazilian President Luiz Inacio Lula da Silva is undergoing treatment for throat cancer.
Chavez said his ally Fidel Castro had repeatedly warned him to beware of what he eats, as foods are potential vehicles for an illness.
The Venezuelan leader questioned the timing of the diagnoses -- Rousseff during her campaign, and Chavez himself right before an election year.
"I repeat: I am not accusing anyone. I am just using my freedom to reflect and give commentary on very strange occurrences that are hard to explain," he said.