The centrist party To Potami condemned an attack of vandalism by the Rouvikonas anarchist group against the US Embassy in Athens on Monday, saying that the assault "compromises Greeks on the international stage."
"How much longer will certain individuals have immunity to continue their actions unhindered?" the party said, noting that even the best-guarded parts of the capital were coming under attack.
"Tolerance of lawlessness and of troublemakers must, finally, come to an end," it added.
The Greek Police was questioning eight people in connection with the attack on the embassy's parking area which was defaced with red paint.
In a claim of responsibility for the pre-dawn attack on an anti-establishment website, Rouvikonas took issue with "American imperialism."