Egyptian security officials say nine suspected Muslim Brotherhood members have been executed after being convicted of involvement in the 2015 assassination of the country's top prosecutor.

The officials, who spoke on condition of anonymity because they were not authorized to brief media, say the executions were carried out Wednesday.

The nine were found guilty of taking part in the bombing that killed Hisham Barakat, the most senior government official killed by Islamic militants since the military's 2013 overthrow of an elected but divisive Islamist president. Egypt's highest appeals court upheld the death sentences in November.

Amnesty International on Tuesday called on Egypt to halt the executions, saying that some defendants said they were forcibly disappeared and confessed under torture.