Egypt's military said that a device it claimed it invented to cure Aids and hepatitis C needs six more months of testing.
The army had earlier promised to reveal the technology to the public today after making what experts dismissed as an outlandish claim last February.
At a news conference then, 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 a satirical programme that has since been taken off the air.
The assertion hit a sensitive nerve in Egypt, where hepatitis C is an epidemic. Some studies estimate that up to 10 per cent of 86 million Egyptians have it, making it the country with the highest prevalence in the world.
In a press conference held in a military hospital in Cairo on Saturday, a military doctor said the blood purification device needed further tests before it could be released to the public.
"Scientific integrity mandates that I delay the start of the public release until the experimentation period is over, to allow for a follow-up with patients already using it," Egypt's state news agency MENA quoted Major General Gamal el-Serafy, director of the Armed Forces Medical Department, as saying.
Serafy said doctors had already started testing one of the machines, the so-called "Complete Cure Device", on 80 hepatitis C patients who were also being treated with medication.
Saturday's news conference notably dropped any mention of the device as a cure for Aids, only referring to hepatitis.
The original claim in February raised concerns that the military's offer of seemingly inconceivable future devices would draw Egypt back into a pattern of broken promises by successive rulers.
Generals working on the project and pro-military media adopted a defensive stance over the matter, insisting that the inventions would be released to the public and that any criticism of them was part of a foreign plot to rob Egypt of a major scientific victory.