A group of armed men ambushed a police truck transporting awaiting prisoners back to Sun City prison on Tuesday afternoon.
Spokesperson for Gauteng Provincial police Colonel Lungelo Dlamini said the men broke a lock to the truck, and freed 20 awaiting trial prisoners.
The men, armed with rifles, ambushed the police truck at Pat Mbatha Road near Southgate train station.
The prisoners had just appeared in court and one of them was already sentenced to 17 years imprisonment after he was convicted for an armed robbery.
He said police are following several leads to arrest the prisoners and the armed group.
Dlamini said the awaiting trial prisoners were charged with various crimes including armed robbery, housebreaking and theft and possession of drugs. Police officers were not injured.
"Further details of the prisoners will be released at a later stage as the investigation was continuing."
Police appealed to anyone who might have information about the suspects who ambushed the truck and the whereabouts of the prisoners to contact Crime Stop on 08600 10111