Demonstrators set at least two police cars on fire Wednesday as authorities confronted left-wing anti-austerity protesters trying to blockade the inauguration ceremony for the European Central Bank's new headquarters in Frankfurt, Germany, ABC news reported.
Police said one officer was injured by stones thrown by demonstrators near the city's Alte Oper opera house.
Police put up barricades and barbed wire around the ECB headquarters as they braced for demonstrations against government austerity measures and capitalism.
Protesters targeted the ECB because of the bank's role in supervising efforts to restrain spending and reduce debt in financially troubled countries such as Greece.
The Blockupy alliance says activists plan to try to blockade the new headquarters of the ECB ahead of a ceremony Wednesday inaugurating the building, and to disrupt what they term capitalist business as usual.
Some 10,000 people were expected for a rally in Frankfurt's main square, the Roemerberg. Organizers have chartered a special train bringing demonstrators from Berlin and are busing in others from around Germany and other European countries.