The New York Times reported a Western diplomat it did not identify said Egyptian officials had privately identified the targeted diplomatic site as the U.S. Embassy in Cairo.
Egyptian Interior Minister Mohamed Ibrahim wouldn't say which embassy was involved but said the suspects were "on the verge" of carrying out their attack.
Ibrahim said the trio had been in contact with an al-Qaida figure in western Asia and "elements responsible for receiving terrorist fighters on Turkey's border" with Syria, Ahram Online reported. Ibrahim said one of the three had traveled to Pakistan and Iran for military training, the Time said.
Ibrahim said police found 10 kilograms (22 pounds) of ammonium nitrate, a common ingredient in homemade explosives, when they arrested the suspects-- Mohamed Abdel-Halim, Mohamed Mustafa and Amr Mohamed -- who allegedly are affiliated with the ultra-conservative Gamaa Jihadiyah group.
Mamdouh Ismail, an attorney for the suspects, told Ahram Online his clients were also suspected of intending to travel to Syria to join al-Qaida's "Al-Nusra Front." Ismail said his clients deny the charges, which they described as "fabricated."
The Times said the U.S. State Department would not comment on the matter. "We don't discuss the specifics of our operations nor the exchanges we have with foreign officials," department spokeswoman Jennifer R. Psaki said.