The Egyptian authorities have arrested an engineer who works at the country's nuclear energy agency for spying for Israel, state prosecutors said.
Egypt hopes to have a power station of its own by 10 years
Prosecutor Hisham Badawi told a news conference the Egyptian national had taken reports from his workplace with the aim of exchanging them for money.
Two foreign nationals are also wanted by the authorities, prosecutors said.
Egypt has a small atomic reactor for research purposes but recently unveiled plans for a civilian nuclear programme.
Israel has denied that the Egyptian engineer was spying for it.
He was arrested on 18 February, but news of his detention was withheld until the investigation was completed, prosecutors said.
A government statement named him as Muhammad Sayed Saber Ali, 35. The foreign nationals were named as Irishman Brian Peter and Shiro Izo of Japan.
Egypt is a signatory to the Nuclear Non-Proliferation Treaty, which allows countries to build nuclear power stations under international supervision.
Israel is not a signatory and is believed to be the only state in the region with a nuclear arsenal, though it maintains a position of "ambiguity" on its nuclear weapons.
The two countries ended decades of hostility with the Camp David accords in the late 1970s, but ties have been put under strain over a string of espionage cases.
Last September, Egypt said it wanted to revive its nuclear power programme, which was frozen 20 years ago following the Chernobyl disaster in the Soviet Union.
Demand for electricity has been growing in Egypt at an average rate of 7% a year and the country faces worsening power shortages.