Forty-five Egyptians accused of supporting deposed president Mohamed Morsi were acquitted on Sunday on charges related to illegal assembly in front of the US embassy in Cairo in August 2013.
The defendants faced charges of protesting in front of the embassy two days following the forceful dispersal of pro-Morsi camps in Cairo and Giza by security forces which claimed the lives of hundreds.
Their charges also included the possession of weapons, assaulting officers, violently resisting their arrest and the attempted murder of three men.
Security forces have cracked down on the Muslim Brotherhood and Morsi loyalists following the popularly-backed ouster of the Islamist president last July, with thousands detained, including the Brotherhood's top leadership, on a variety of charges.
Islamist militants have launched attacks on army and police officers across the country which have killed hundreds. The Brotherhood, designated a terrorist group in December, has vehemently denied any links to the attacks.