Dozens of people have been hurt and some 350 people arrested as anti-austerity demonstrators clashed with police in the German city of Frankfur, the BBC reports.
Police cars were set alight and stones were thrown in a protest against the opening of a new base for the European Central Bank (ECB).
Violence broke out close to the city’s Alte Oper concert hall hours before the ECB building’s official opening.
Thousands of “Blockupy” activists were due to take part in a rally.
Organisers were bringing a left-wing alliance of protesters from across Germany and the rest of Europe to voice their anger at the ECB’s role in austerity measures in EU member states, most recently Greece.
The bank, in charge of managing the euro, is also responsible for framing eurozone policy and, along with the IMF and European Commission, has set conditions for bailouts in Ireland, Greece, Portugal and Cyprus.