There are no immediate reports of injuries or damage.
Athens mayor insists the statue's installation has nothing to do with the ongoing Greek dispute with Macedonia.
No one was hurt by the grenade blast.
For many Greeks, the name 'Macedonia' belongs to Greek historical heritage.
Non-fatal attacks targeting centres of power and embassies have been common in Greece in recent years.
The attack was carried out by about 10 Rubicon members who, armed with iron bars, took the guard by surprise and then smashed windows in the waiting room.
Stefanos Tsitsipas believes that Athens is capable of hosting an ATP tournament, something it hasn't done since 1994.
Deputy Citizen Protection Minister Nikos Toskas on Thursday suggests there were "serious" signs that the worst of the fires were the result of arson.
The Rouvikonas group said the attack was linked to the Palestinian-Israeli conflict.
Sting also lauded the Greek governments' actions towards refugees.
Dimitrios rarely visited the village but those who did say he was quiet and did not show signs of unusual behaviour.
The boat was ferrying migrants from Turkey to Greece.
The fishing boat attempted to flee unsuccessfully and was escorted to the port of Ierapetra in Crete, where checks revealed the load of cannabis, worth about €15 million.
As a protest against upcoming reforms to be passed by the Greek government, the Athens subway did not operate, and ships could not sail, as many went on strike.