People wearing carnival masks threw Molotov cocktails at the Athens headquarters of Greece’s ruling Syriza party on Sunday, causing slight damage.

Police said one officer was injured and 35 suspects were being held for questioning.

Authorities said the group threw five petrol bombs at the building’s entrance and at two cars parked outside.

The attack, which blackened the walls of the building, came as euro zone finance ministers are set to meet on Monday to discuss what more austerity measures Greece needs to carry out to get fresh bailout money.