The ISIS-affiliated militant group in Egypt, Wilayet Sinai, or the Sinai province, posted an audio recording on Wednesday, vowing to avenge “those killed by the army and police.”
According to witnesses, Sinai province militants went door to door delivering leaflets explaining their intentions.
The militant group in North Sinai killed dozens of Egyptian soldiers and police in the past two years.
"It is wrong for the tyrants to jail our brothers," cleric Abu Osama al-Masry said, referring to the judges.
"Poison their food, surveil them at home and in the street, destroy their homes with explosives if you can."
Any full-blown campaign against judges could spell trouble for President Abdel Fattah al-Sisi, who as army chief removed the Muslim Brotherhood from power in a military coup in 2013.
Hundreds of Muslim Brotherhood supporters were killed in massacres in Cairo’s Rabaa and Nahda camps and thousands of others were arrested and given harsh penalties.
It came only a few days after deposed president Mohamed Morsi was given the death penalty along with more than a 100 other defendants over allegations of providing espionage to Hamas.
The Brotherhood is a peaceful movement determined to return to power through street protests even though its top leaders are in prison.
In a move which renewed the spotlight on Egypt’s justice system and the struggle against militancy Egypt appointed a hardline judge and outspoken critic of the Brotherhood as justice minister on Wednesday.
Ahmed el-Zend, a former appeals court judge, has in contrast to his predecessor been publicly outspoken in his criticism of the Brotherhood, which has been banned as a terrorist organisation.
His appointment was decried by a leading opposition figure as a disaster for justice in Egypt, a country which is a strategic US ally and has faced off against militancy for decades.
"The appointment of someone like Ahmed el-Zend sends a clear message that the confrontation with the Brotherhood and Islamists in general will continue and perhaps even intensify," said Shadi Hamid, fellow at the Brookings Institution.
"Any kind of hope that the regime would start to pull back and lessen the degree of repression doesn't seem likely."