U.N. experts have found traces of plutonium near an Egyptian nuclear facility and are investigating whether it could be weapons-related or simply a byproduct of the country's peaceful atomic activities, diplomats told The Associated Press on Friday.

The diplomats, speaking on condition of anonymity, warned against assuming that Egypt might have contravened the Nonproliferation Treaty (search) by trying to separate plutonium, a substance used in nuclear weapons.

The traces could be from a cracked research reactor fuel element or have other origins that have nothing to do with weapons research, they said.

"From time to time, these things pop up in places they should not be at," said a diplomat familiar with the investigations of the Vienna-based International Atomic Energy Agency (search). "Most of the time, there is a reasonable answer."

Still, he said IAEA experts were considering all scenarios that would explain the origin of the particles pending the completion of analysis of the environmental samples in several European laboratories.

The diplomat said the IAEA's information was still too sketchy to firmly establish how old the plutonium (search) traces were but suggested they appeared to have been released into the environment no later than the 1980s.

Egypt appeared to turn away from the pursuit of a nuclear weapons program decades ago. The Soviet Union and China reportedly rebuffed its requests for nuclear arms in the 1960s, and by the 1970s, Egypt gave up the idea of building a plutonium production reactor and reprocessing plant.

Egypt runs small-scale nuclear programs for medical and research purposes. Plans were floated as recently as 2002 to build the country's first nuclear power reactor, but no construction date has been announced.