Former Egyptian President Mohamed Morsi stands inside a glass defendant's cage during the hearing in police academy in Cairo, Egypt on May 16, 2015. [Photo/IC]

Only two hours after the Cairo Criminal Court sentenced Morsi and dozens of Muslim Brotherhood (MB) leaders and affiliates to death over jailbreak and espionage charges, a group of militants opened fire at a car carrying judges in Al-Arish City, killing three of them together with their driver.

Three other judges were critically injured in the attack.

Police rushed to the scene, cordoned off the area and started an investigation to identify the assailants.

No groups have claimed responsibility for the attack. However, analysts say it is more likely that the assault was carried out by the Sinai-based Ansar Bayt al-Maqdis, which has recently pledged allegiance to the Islamic State (IS) regional militant group.

Saturday's attack raised fear that judges will be the new targets for militants who have been targeting army and policemen across the country.

This urged Egyptian President Abdel-Fattah al-Sisi to order security forces to provide protection for workers of the judicial system, according the State TV.

Military operations escalated notably in restive Sinai Peninsula after the ouster of Morsi by the army in response to mass protest against his one-year rule in 2013.

Anti-government attacks have extended lately to reach the capital Cairo and other provinces across the country.

Meanwhile, Saturday's Cairo Criminal Court ruling was the first death sentence against an Egyptian leader in modern history.

The former president and 105 other defendants, most of whom are members of the Palestinian Hamas group, were sentenced to death over 2011 jailbreak in the case publicly known as the "Wadi al-Natron jailbreak."