The court slapped ten defendants with a life sentence each in absentia for attacking a police station in southern Egypt, Ezzat Ghoneim, the director of the Cairo-based Egyptian Coordination for Rights and Freedoms (ECRF), told Anadolu Agency.
Seven people were also jailed for 15 years on the same charges, he said.
The verdict is still subject to appeal.
Egypt has been roiled by turmoil since the military deposed Mohamed Morsi, the country’s first freely elected president, in a 2013 coup.
In 2014, Abdel-Fattah al-Sisi, a former army chief who led the military to oust Morsi, approved legislation allowing individuals accused of committing violations against state institutions to be referred to military courts.