Some two dozen demonstrators gathered at the Doctors' Association in the Egyptian capital on Tuesday, demanding that the army release information about a promised cure for AIDS and hepatitis it has delayed since last year.
The military's engineering wing made the widely ridiculed claim that it had invented devices that could detect and cure the diseases, but last summer said it needed until the end of December to carry out further tests before releasing them to the public.
Last month, prosecutors ordered an investigation into the devices, after a lawyer filed a complaint against the inventors, who include a now-retired army chief engineer and another military officer. The complaint accused the inventors of misleading the public.
"If it is working, they should say so. Otherwise they should apologize to the patients who have been waiting for this miracle cure for the past year," said Mohammed Fattouh, a doctor and Association board member. "And in that case they must hold some people to account and make sure mistakes like this do not happen again."
The demonstrators, mostly doctors, stood on the steps of the association's building in order to avoid arrest for unauthorized protest. Thousands sit behind bars in Egypt as a result of a draconian protest law decreed during a crackdown following the 2013 military overthrow of the Islamist president, Mohammed Morsi.
At a news conference last February, the head of the army's Engineering Agency said the military had produced an "astonishing, miraculous" set of inventions that could detect AIDS, hepatitis and other viruses without taking blood samples and also purify the blood of those suffering from the diseases.
The claim caused uproar among scientists and the public, with many pointing out that the technology had not been properly verified. It was also lampooned in the local and international media.
The assertion hit a sensitive nerve in Egypt, where Hepatitis C is an epidemic. Some studies estimate that up to 10 percent of 86 million Egyptians have it, making it the country with the highest prevalence in the world.
Military officers involved in the project declined to comment.