Egypt's ambulance authority head Ahmed El-Ansary announced on Friday that at least nine were injured after a tram in Cairo's Nasr City crashed into two cars.
The accident occurred after supporters of deposed president Mohamed Morsi allegedly threw Molotov cocktails at a tram line near Al-Nozha street in Nasr City, setting a train carriage and a nearby kiosk on fire.
According to El-Ansary, the injured were transferred to the nearby Heliopolis and Manshyiet El-Bakri hospitals.
Pro-Morsi protesters took the streets on Friday to mark 100 days since a violent security dispersal of two Islamist protest camps left hundreds dead in August.
Thousands marched in a number of Cairo districts, as well as in Alexandria, the Upper Egypt city of Assiut, the Nile Delta cities of Kafr El-Dawwar and Damietta, and the Suez Canal city of Suez, reported Al-Ahram's Arabic website.
The protests, which turned into clashes in several places, left a 10-year-old dead in Suez, as well another killed in Minya and 15 injured nationwide, according to Middle East News Agency (MENA).