An Egyptian court on Thursday sentenced a former advisor to toppled president Mohammed Morsi, along with 13 other people, to life in prison for belonging to an illegal group, AFP reported.
Abdullah Shehata was an economic advisor to the Muslim Brotherhood-affiliated president, who was democratically elected in 2012 following the overthrow of longtime former President Hosni Mubarak.
Morsi was ousted by the army in 2013 amid mass protests against his rule.
Shehata and the 13 others sentenced to life terms were accused of weapons possession, belonging to an illegal group and "violating citizens´ freedoms", according to AFP.
The prosecution accused them of creating "special cells" to receive training in how to make sound bombs, the state-run newspaper Al-Ahram reported.
They were planning to cause "a state of instability in the country" by targeting essential infrastructure, including electrical transformers, it said.
Six other people were sentenced to 15 years in prison and another to 10 years over the same case, according to state television.
Egypt has intensified a long-running crackdown on dissent since President Abdel-Fattah Al-Sisi's re-election in March.
The arrests are part of a wider crackdown on dissent since the 2013 military ouster of Islamist President Mohammed Morsi of the Muslim Brotherhood, following mass protests against his one-year rule.
As part of the crackdown, thousands of Brotherhood supporters have been jailed and the group was blacklisted as a terrorist organization.
Last May, an Egyptian court sentenced the Muslim Brotherhood's supreme guide, Mohammed Badie, to life in prison for "planning violent attacks".
Earlier this year, Egypt froze the assets of leading government critic Abdel Moneim Abul Fotouh, weeks after he was arrested over alleged links to exiled members of the Muslim Brotherhood.
Morsi himself has been sentenced to decades in prison in several cases, including one alleging he used unauthorized violence, arrest and torture to put down a protest outside the presidential palace, and another based on his leadership position in the now-banned Muslim Brotherhood group. Other cases are still pending.
Last September, a court in Egypt upheld a life sentence against Morsi on charges stemming from a trial over spying for Qatar.
In November of 2016, Egypt's court of cassation overturned a life sentence against the Islamist former President in a case that revolves around accusations of espionage with Hamas.
A week earlier the court overturned a death sentence against Morsi in a case in which he and five other leaders of the Muslim Brotherhood were sentenced for their roles in organizing a mass prison break in 2011.
In 2012, he was sentenced to 20 years in prison after being convicted of inciting the killing of protesters, in an incident that saw 10 people gunned down outside the presidential palace in December 2012.