Guatemala has made a formal request for full disclosure on the manner by which the US scientists infected hundreds of people with sexually transmitted diseases from 1946-1948.
"All of the information has been requested officially but it is still at the university where they found the archives," President Alvaro Colom said of the cases of 1,500 Guatemalans who were used unwittingly in testing that some locals have likened to Nazi experiments.
In a phone conversation with Colom on Friday, US President Barack Obama expressed his deep regret for the experiment conducted by US public health researchers six decades ago and apologized "to all those affected."
The study, which was never published, came to light this year after Wellesley College professor Susan Reverby stumbled upon archived documents outlining the 1940s experiment led by controversial US public health doctor John Cutler.
Cutler and his fellow researchers enrolled people in Guatemala, including mental patients, for the study, which aimed to find out if penicillin, relatively new in the 1940s, could be used to prevent sexually transmitted diseases.
Cutler, was also involved in a highly controversial study known as the Tuskegee Experiment in which hundreds of African American men with syphilis were observed but given no treatment for 40 years, between 1932 and 1972.
Colom, who has formed a panel to investigate, said it was "important for Guatemala as a nation to get the investigation done as soon as possible."
At least one patient died during the experiments, although it is not clear whether the death was from the tests or from an underlying medical problem.