An Egyptian military court on Thursday sentenced seven Muslim Brotherhood members to 15 years in jail for attacking police stations in Assiut in August 2013.
Eleven other members of the outlawed group were sentenced to 25 years in prison each in absentia in the same verdict.
The defendants were convicted of throwing a bomb at a police station, part of a wave of attacks on state and security targets in the aftermath of the deadly dispersal of the Rabaa El-Adawiya protest camp in Cairo in the same month.
According to Egyptian law, defendants sentenced in absentia automatically receive retrials when they turn themselves in.
The verdicts can still be appealed.
Egypt's government has banned the Muslim Brotherhood, declaring it a terrorist organisation in October 2013.
In October 2014, Egypt allowed military courts to try civilians accused of attacking state facilities or blocking roads for two years, following deadly assaults that killed dozens of security forces in the Sinai Peninsula.
Last week, President Abdel-Fattah El-Sisi extended this provision for five more years.