Unidentified vandals damaged SYRIZA offices in the central Athens Petralona district and the Kalamaria neighborhood of Thessaloniki, in the early hours of Friday, police said.
In a separate incident, a group of about 15 anarchist suspects clashed with riot police near the house of State Minister Alekos Flambouraris, in the central Athens Exarchia district, police said.
There were no reports of arrests.
This is the fourth time that attackers have targeted the residence of Flambouraris, a close adviser to Prime Minister Alexis Tsipras, since November.
Friday’s attacks took place in the wake of Wednesday’s forcible evacuation of anti-establishment protesters – chiefly foreigners that participated in Thessaloniki’s pro-refugee No Border Camp – from three occupied buildings in the northern port city.
On Thursday, SYRIZA’s Group of 53 faction – self-appointed guardian of the leftist party’s ideology – accused the government of embracing a “law and order” mentality.