''There was a controlled explosion of a bag placed near
Citibank after we were told it would go off in 35 minutes,'' a police official said.
Security has been an issue throughout Greece ahead of this
summer's Olympic games and amid widespread concern in Europe after the bomb blasts on Madrid trains on Thursday.
Police found two sticks of dynamite, a clock and a detonator in the remains of the bag and a police source said the bomb was not sophisticated but was powerful enough to cause ''death and damage''.
There was no claim of responsibility, the official said.