Colombian police are investigating the discovery of a box containing radioactive material, including uranium and plutonium, which has prompted a major security alert in the city of Cali.

Specialist police and fire units as well as Colombian air force officials attended the scene in the neighborhood of El Troncal, in the north east of the city, on Monday afternoon after the alarm was raised by local residents.

Several streets were cordoned off and homes and businesses evacuated as teams in hazmat suits investigated the polystyrene container. It was feared the box could contain a bomb; however instead, two bars of radioactive material weighing approximately five kilos (11lb) were discovered, composed of uranium, plutonium and iridium.

After a five-hour operation in the neighbourhood, a radiological emergencies team was sent in to remove it to an unnamed site in an unpopulated area for final disposal.