Egyptian scientists have been caught out by the United Nations nuclear watchdog for not declaring tests that could be used in weapons programmes.
Inspectors with the Vienna-based International Atomic Energy Agency (IAEA) detected trace material from small-scale experiments as a result of environmental sampling in Egypt over the past four months.
But diplomats in Vienna played down the discovery, saying that the experiments did not involve uranium enrichment which would have provided a clear indication that Egypt was working on a nuclear weapons programme.
Asked whether the discovery was likely to cause international alarm, as did the recent concealment of South Korean tests, the diplomat replied: "It's much less than the South Korean model and not so focused."
The Egyptians "tried to produce various components of uranium" without declaring it to the IAEA, as they were bound to under the nuclear non-proliferation treaty. South Korea, however, provoked serious concern at the IAEA that it was actively engaged in a weapons programme by failing to report uranium enrichment.
Egypt signed the non-proliferation treaty in 1968 but delayed ratification for 13 years, apparently after discovering that Israel had embarked on a nuclear weapons programme. It could be that some of the samples found by the IAEA inspectors may be linked to work dating back two decades.
In Cairo, a government spokesman, Magdy Rady, said Egypt had only a peaceful nuclear programme. "We don't have a secret programme for energy," he said. "All our programme is known."