Three Egyptian judges have been gunned down hours after a ruling sentencing former president, Mohamed Morsi, to death was read.
Morsi was deposed in August 2013, his party banned and hundreds of its former officials and supporters arrested and jailed.
Sinai borders the Gaza strip and Egyptian state prosecutors have claimed that Mr Morsi colluded with the Palestinian Hamas group while his predecessor was being overthrown during the Arab Spring.
They alleged that during the 18-day uprising in 2011, militants passed through illegal tunnels between Gaza and Sinai to enter Egypt and help hundreds of Muslim Brotherhood supporters, including Mr Morsi, escape jails in the capital in violent prison breaks.
Mr Morsi has also faced charges relating to the killing and torture of protesters, passing state secrets to Hamas, Hezbollah and Qatar, fraud and “insulting the judiciary”.
Morsi was among more than 100 defendants given the death penalty Saturday for their role in a mass jailbreak during the 2011 uprising.
He was sentenced Saturday to death.
Killing of judges
The judges were travelling in a car in the city of al-Arish, Sinai, when it was attacked by suspected Islamist gunmen in an assault that left another person dead and three more injured.
Al-Arish is just 30 miles from the Rafah crossing between Egypt and the southern Gaza Strip.
Egypt’s interior ministry said a policeman was also killed on Saturday in the outskirts of Cairo by gunmen on motorcycles.
The shootings came days after another judge was the victim of an assassination attempt.
Moataz Khafagi, who sentenced 12 Muslim Brotherhood members to death last year after convicting them of killing a police general, survived bomb blasts outside his home in Cairo suburb that damaged several cars but caused no casualties.
US expresses alarm
The United States expressed alarm Sunday at death sentences for Morsi and dozens of others.
He ruled for only a year before mass protests spurred then army chief and now President Abdel Fattah al-Sisi to overthrow him in July 2013.
Sisi won a presidential election in May 2014 backed by Egyptians tired of political turmoil in the world’s most populous Arab nation following the 2011 revolt against longtime autocrat Hosni Mubarak.
Washington expressed concern over Saturday’s verdict, saying it has consistently spoken out against the practice of mass trials and sentences.
“We continue to stress the need for due process and individualised judicial processes for all Egyptians in the interests of justice,” a State Department official said.
The foreign ministry denounced global condemnation of the verdict as “unacceptable interference in the internal affairs of the country”.
Ties between Washington and Cairo plummeted after Morsi’s ouster, with President Barack Obama’s adminstration freezing annual military aid of $1.3 billion to Cairo.