Egypt upholds death penalty for 12 Brotherhood members: judicial sources
The court of cassation also reduced sentences for 31 other Brotherhood members, in the trial relating to a 2013 mass killing by security forces at a peaceful sit-in, to life in prison, the official told AFP.
Those condemned to death were convicted of "arming criminal gangs which attacked residents and resisted policemen as well as possessing firearms and ammunition... and bomb-making material", the court said in its ruling.
Other charges include "killing policemen... resisting authorities... and occupation and destruction of public property", it added.
The rulings are final and cannot be appealed, the judicial source said.
Egypt's former democratically elected president Mohamed Morsi, head of the political wing of the Muslim Brotherhood, held power for a year before being ousted by the military in 2013.
Egyptian authorities outlawed the Islamist group in 2013 and have since overseen a wide-ranging crackdown that has jailed thousands of its supporters.
The original case, dating back to 2013, had over 600 defendants and is locally known as the "Rabaa clearing case".
Rabaa Al-Adawiya Square in eastern Cairo was the site of a massive protest camp calling for the return of Morsi after his ouster.
Security forces raided and killed hundreds of people in a single day in August 2013, a few weeks after Morsi's overthrow.
In 2018, an Egyptian court sentenced 75 of them to death and the rest to varying jail sentences, including 10 years for Morsi's son Osama.
Human rights groups have dubbed it the deadliest incident in modern Egyptian history.
Authorities claimed at the time that Muslim Brotherhood members were armed and the forced dispersal was a vital counter-terrorism measure.