Organisers of the Games, who have spent hundreds of millions on security so far, will be reviewing plans after a police station in Athens was hit three times.
No-one was hurt, and a warning sent to a city newspaper, had ensured authorities could evacuate the area before the devices were detonated.
It is understood senior police figures have ruled out any connection to the Olympic Games.
According to reports, the station was in the Kalithea area – close to several hotels due to be used by Olympic officials during the summer Games which get underway in August.
The blasts are just the latest headache for ATHOC, the local organising committee. It is already under fire for delays in construction of the major venues.
