Rights groups said some of accused had been forcibly detained and tortured to confess during their trial. The human rights situation in Egypt has rapidly deteriorated under President Abdel-Fattah el-Sissi.
Nine suspected Muslim Brotherhood members convicted for the 2015 assassination of Egypt's top prosecutor have been executed, security sources said Wednesday.
He was the highest profile figure killed by Islamist militants since the military in 2013 overthrew democratically elected President Mohammed Morsi of the Muslim Brotherhood.
Egypt's highest appeals court upheld the death sentences against the nine accused in November.
Amnesty International earlier in the week had called on the government to halt the executions.
"Some of the defendants said they were forcibly disappeared and tortured to confessing to the crime" during their trial, Amnesty said. "Executing prisoners or convicting people based on confessions extracted through torture is not justice."
President Abdel-Fattah el-Sissi has implemented a severe security crackdown on the Muslim Brotherhood and Islamist militants since the ouster of Morsi.
The coup helped fuel a deadly insurgency in the country.