Moufid Deak, spokesman for the US Embassy in Cairo, says Ahmed Aleiba, an Egyptian citizen who works at the embassy, was arrested on January 25, the anniversary of the uprising that deposed former President Hosni Mubarak in 2011.
A security official, who spoke on the condition of anonymity because he was not authorised to speak to the media, confirmed Aleiba's arrest.
Military-aligned newspaper Al-Watan published an article in July mentioning Aleiba as an employee who arranged meetings between visiting American government officials and Muslim Brotherhood deputy head Khairat el-Shater.