Clashes between police forces and extreme left anti-establishment groups broke out around the area of the Polytechnic University, in downtown Athens, Wednesday evening. About 100 anarchists barricaded themselves in the university’s yard and started throwing firebombs, flares and other objects against riot police that formed a line around the building. Police responded by making extensive use of tear gas, while at least two rioters were arrested. Patision Ave. was cordoned off until 3.30am due to the clashes. Scuffles between anarchists and police in and around the Exarchia area, close to the Polytechnic, are a common occurrence and often ignite for the most trivial reasons.