Two bombs exploded on Giza Bridge on Friday morning, apparently targeting Central Security Forces trucks deployed on the bridge, Al-Ahram Arabic website reported.
Head of Giza central security, Mostafa Ragaei, said in a televised interview with CBC channel that at least two CSF personnel have been confirmed injured.
The health ministry released a statement shortly afterwards confirming that there were no deaths as a result of the explosion, and that six people were injured.
According to Al-Ahram Arabic, initial investigations show that two improvised bombs were thrown at the same time at a CSF truck, damaging its door and breaking the window of another private car passing by. The area was sealed off and inspected as ambulances rushed to the scene.
Security forces were deployed around nearby Giza Square early on Friday ahead of expected Friday protests. The square was the site of a major vigil supporting ousted president Mohamed Morsi over the summer, until its dispersal in August.
Security was also deployed in several areas around the capital, near Rabaa Square the site of the other main pro-Morsi camp, and around Tahrir Square.
Morsi was ousted on 3 July amid mass protests against him. His supporters have been holding regular protests demanding his reinstatement.
Violence escalated between Morsi supporters and security forces since the violent dispersal of the two main sit-ins last August which left hundreds killed. Police and army have become frequent targets of militant attacks.