Two explosive devices detonated inside a private car in greater Cairo's 6 October city on Tuesday, killing three people inside the car, next to the Nakheel shopping center near the 6 October police station, health ministry spokesman Hossam Abdel-Ghaffar told private channel CBC Extra.
The ministry announced that three people were also injured during the blast, state-news agency MENA reported.
Eye witnesses said the car was on its way to the police station, 1.1 km away from the Nakheel shopping centre.
According to security investigations, the car was blocked by a fight between two tok-tok drivers in Gamal Abdel-Nasser street. They then drove faster, triggering the explosion as the bomb went off after being shaken by the car's sudden move, according to Ahram's Arabic news website.
When it went off, a passerby approached the car and was killed by the second device's explosion, according to eyewitnesses.
One body was deformed, another turned into pieces and the passerby's was torn apart.
The body parts were transferred to Zeinhom morgue for DNA examinations, Al-Ahram added.
The explosion comes a day after Egypt's top prosecutor was killed, after a car bomb targeted his convoy near the military academy in Heliopolis.
Militants have targeted security personnel as well as infrastructure installations like electricity pylons with dozens of small bombs planted nationwide in recent months.
An Islamist insurgency that has killed hundreds of security personnel in North Sinai had spilled over to the rest of the country.