Egypt's public prosecutor, Hisham Barakat, has been killed in a bomb attack on his car in Cairo, officials say.
Mr Barakat died of his wounds in hospital after the bombing in the suburb of Heliopolis, a government spokesman told the BBC.
State media said that at least eight others were also hurt in the attack.
Mr Barakat has sent thousands of Islamists for trial since the overthrow of President Mohammed Morsi in 2013.
Hundreds of Islamists have been sentenced to death or life imprisonment, as part of a crackdown on supporters of the banned Muslim Brotherhood.
Jihadist militants have meanwhile stepped up their attacks on Egypt's security forces.
Mr Barakat is the most senior figure to have been targeted for assassination since a 2013 attempt on the life of the then-interior minister.
"He [Mr Barakat] has passed away," Justice Minister Ahmed al-Zind told AFP news agency.
The Egyptian state news agency Mena said that he had died after undergoing critical surgery. A medical official at the hospital told the Associated Press that Mr Barakat had received multiple shrapnel wounds to the shoulder, chest and liver.
Monday's attack involved a car bomb or an explosive device placed under a parked car near Mr Barakat's convoy, bomb squad chief Gen Mohamed Gamal told AFP.
The explosion sent black smoke rising over the neighbourhood and set fire to nearby trees. Images from the scene showed several damaged vehicles and bloodstains on the streets.
At least three civilians were killed, according to Mena. Witnesses said that the blast had been strong enough to shatter the windows of nearby homes.
At the hospital, an injured bodyguard said that the explosion had hit Mr Barakat's convoy on the way to the office.
"There was glass flying everywhere. It was as if there was an earthquake," he said, according to AFP.
Mr Barakat had received death threats in the past.
The Egyptian affiliate of the Islamic State militant group recently called for attacks on the judiciary, after the hanging of six militants.