The US State Department on Thursday denounced the Venezuelan President Hugo Chavez for questioning whether the U.S. might be guilty of causing cancers affecting Latin American leaders.

Government spokesperson Victoria Nuland said the comments were “horrific and reprehensible” and were not worthy of further response.

The Venezuelan leader stated in a broadcast it was “very strange” that he and leaders from Argentina, Brazil and Paraguay have all struggled with cancer recently. He made the announcement after an official announced on Tuesday that Argentine President Cristina Fernandez de Kirchner also had cancer.

He said that the coincidences of cancer among South American leaders were difficult to explain using “the law of probabilities”, and asked, in a televised speech to soldiers at an army base, if it would be strange if the U.S. had developed technology to induce cancer and nobody knew.

Chavez said that the Central intelligence Agency had been responsible for chemical experiments in Guatemala in the 1940s. He said that the U.S. had only revealed this last year, and that it’s possible that in the future a plot would be uncovered to show that the U.S. spread cancer as a weapon against its critics.

In October 2010 it was reported that from 1946 to 1948, American doctors had purposely infected around 700 Guatemalans. The doctors infected prison inmates, mental patients and soldiers with sexually transmitted diseases to test the effectiveness of penicillin, according to a report in The New York Times.

The U.S. National Institutes of Health used American dollars to pay for prostitutes infected with syphilis to sleep with prisoners, and when the prostitutes did not succeed in infecting the men, some prisoners had bacteria poured onto cuts made on their penises or other body parts.

The Secretary of State Hillary Clinton and Health and Human Services Secretary Kathleen Sebelius apologized to the people of Guatemala and called the experiments “clearly unethical”.

Regarding his latest comments, Chavez said he was just thinking out loud and not making “rash accusations.”