Police in central Athens were placed on alert on Saturday morning after a street cleaner discovered a plastic bag containing the explosive TNT next to the offices of OTE Telecoms. The bag had been left on top of a dumpster on Patission Street. Bomb disposal experts took the bag and its contents away for testing. Scientists confirmed that the bag contained some 250 grams of TNT. Officers said the explosive had not been attached to a timing device, leading them to believe that it was left by unspecified individuals who feared that they were being watched by authorities. Police said that soon afterward an anonymous caller told officers that there was a suspicious package under a car in Exarchia, central Athens. But a check by officers revealed that it was just an empty briefcase.