The Greek protests are getting ugly.

Clashes broke out between the riot police and protestors at the Syntagma Square in front of the Greek parliament. The police had to resort to firing tear gas shots.

The protestors who instigated the violence were youths wearing gasmasks and face-covering scarves, reported Reuters. They hurled stones at the police, set fire to two vehicles, and smashed the windows at a McDonald's restaurant, reported Bloomberg.

In all, four police officers were injured, multiple protesters were injured and treated for breathing troubles, and eighteen protestors were detained.

Greece is facing massive protests in the face of new austerity measures the European community is pressuring the Greek government to pass as a condition for receiving bailout money.

On Tuesday, about 20,000 (largely peaceful) protesters showed up in Athens. Labor unions have also begun a 48-hour general strike, bringing many public services in Athens to a standstill.

Greek Prime Minister George Papandreou is stuck between a rock and a hard place. On the one hand, he faces the outpouring of resistance from his own people. On the other hand, a Greek national default threatens to cut off funding for the government and substantially lower the living standards of all Greek citizens.