Air raid sirens to sound across Greece on Tuesday

Civil defense sirens are expected to go off around Greece on Tuesday as part of an annual military and public warning exercise dubbed Parmenion after the Macedonian general who served Philip II and Alexander the Great.

Authorities have told citizens not to be concerned when they hear air-raid sirens. 

The sirens are scheduled to start at 11 a.m., with interrupted blasts sounding for 60 seconds, and to sound again at 11.05 a.m., one long blast lasting 60 seconds.