Crime scene investigators investigate the site of a car bomb attack on the convoy of Egyptian public prosecutor Hisham Barakat near his house at Heliopolis district in Cairo. AFP

Reuters/Cairo

Egypt's top public prosecutor died on Monday of wounds sustained in a car bomb attack on his convoy as it was leaving his Cairo home on Monday in a marked escalation of Islamist militant attacks on the judiciary.

Judges and other state officials have increasingly been targeted by radical Islamists opposed to President Abdel Fattah al-Sisi and angered by hefty prison sentences imposed on members of the now-outlawed Muslim Brotherhood.

Monday's attack claimed the most senior state official since Sisi, a former army chief, ousted Islamist president Mohamed Mursi in 2013 after mass protests against his rule. Mursi was sentenced this month to death over a mass jailbreak in 2011.

State media, medical and judicial sources confirmed the death of chief prosecutor Hisham Barakat at a hospital in the residential district of Heliopolis where he had undergone surgery hours earlier.

Health ministry spokesman Hossam Abdel Ghaffar had earlier said that Barakat suffered a dislocated shoulder and a deep cut and may have fractured his nose.

There was no confirmed claim of responsibility for the attack, in which security sources said a bomb in a parked car was remotely detonated as Barakat's motorcade passed by. They initially said a car bomber had rammed into the convoy.

The state news agency MENA said the bomb blast also wounded at least nine other people including police and civilians.

Last month, the Islamic State militant group's Egypt affiliate urged followers to attack judges, opening a new front in an Islamist insurgency in the world's most populous Arab country. Earlier in May, three judges were shot dead in the northern Sinai city of al-Arish.

Eyewitnesses said Monday's bombing was strong enough to shatter glass in nearby storefronts and homes. A large plume of black smoke and several smouldering cars were seen near a row of apartment buildings.

Barakat's place of work was also targeted earlier this year when a bomb exploded near the High Court in central Cairo, killing two people.

 Sinai insurgency

 Egypt is facing a Sinai-based insurgency that has killed hundreds of policemen and soldiers since Mursi's fall. The most active group is Sinai Province, which has pledged allegiance to Islamic State, the ultra-hardline jihadist group that has seized control of significant areas of Iraq and Syria.

A video titled "Eliminating the Judges" was published by the group's media arm on Sunday, showing gunmen firing on a vehicle they said was transporting judges. Reuters could not verify the authenticity of the video.

At least two people were killed and 12 wounded in a blast later on Monday likely caused by a roadside bomb near Sheikh Zuweid in North Sinai, security sources said.

A presidential spokesman told MENA that the interior ministry would increase security measures ahead of the June 30 anniversary of the toppling of Mursi, including heightening the alert level and reinforcing security at vital installations.

Justice Minister Ahmed el-Zind, who is seen as a hardline judge and outspoken in his criticism of the Brotherhood, said before the news of Barakat's death that the attack would not deter Egypt's judges and public prosecutors from carrying out their "their patriotic duty that the constitution entrusts them to do in going after terrorist elements and other criminals".

The Egyptian judiciary says it is independent of the government and military. But some of Egypt's judges have drawn accusations of blatant bias by handing down lengthy jail terms and mass death sentences against Islamists.