A firebomb has been thrown at the Turkish consulate in the northern Greek city of Thessaloniki, authorities reported.
Police said three men with crash helmets threw a Molotov cocktail towards the consulate, aiming for the police guards outside the building. The firebomb caused no damage or injuries.
Greek government spokesman Giorgos Petalotis condemned the attack which he said had endangered the safety of the police guards.
He described the attack as inexcusable, adding that the culprits would be caught and brought to justice.
Greece and Turkey have often had tense relations, but attacks against Turkish diplomatic missions are rare.
However, police have increasingly been targeted since the riots of December 2008, sparked by the fatal police shooting of a teenager in Athens.