A senior al-Qaeda operative identified as Saif al-Adel, who was reported to have briefly taken over the network's leadership after Osama Bin Laden's death, has been arrested in Egypt, security officials say Al JAzeera reported
Al-Adel, who is on the FBI's most-wanted list with a reward of up to $5m for his capture, was detained at Cairo airport on Wednesday.
Officials said he had arrived on an Emirates Airline flight from Pakistan with a stop over in Dubai.
Security officials said the al-Adel, a former Egyptian army officer, was arrested after presenting a travel document at customs and taken into custody by the National Security apparatus.
The FBI said on its website that al-Adel "is thought to be affiliated with the Egyptian Islamic Jihad (EIJ), and is believed to be a high-ranking member of the al-Qaeda organisation".
He was wanted since 1994 in connection with the August 7, 1998, bombings of the United States Embassies in Dar es-Salaam, Tanzania, and Nairobi, Kenya.
An airport source speaking to Al Jazeera said al-Sadel told reporters at the airport that he left al-Qaeda long time ago.