Police Cars Set Alight at Austerity Protest in Germany

Several thousand riot officers pursued what they said was a minority of violence-minded activists as the bulk of protesters conducted themselves peacefully ahead of a rally in the city's main square. Some blocked bridges across the Main River or streets.

Police said one officer was injured by stones thrown near the city's Alte Oper opera house, several private vehicles were burned overnight, and two police cars were set on fire at a police station in the city center. Another police vehicle smoldered a block from the ECB, AP reported.

Hundreds of officers ringed the ECB headquarters ahead of the inauguration ceremony. Protesters are targeting 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 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.

Frankfurt police say most demonstrators are expected to be peaceful, but that violence-prone elements could use the crowds as cover. Participants include trade unions and Germany's Left Party.

The ECB, along with the European Commission and International Monetary Fund, is part of the so-called "troika" that monitors compliance with the conditions of bailout loans for Greece and other financially troubled countries in Europe. Those conditions include spending cuts and reducing deficits, moves that are aimed at reducing debt but have also been blamed for high unemployment and slow growth.

Anti-austerity activists received a political boost when Greece's Syriza party won elections there in January by campaigning against the bailout deal and its conditions, which they say has led to a "humanitarian crisis." Refusal of the conditions, however, has led to the withholding of further aid and the possibility of a chaotic debt default by the government.

ECB President Mario Draghi has called for more spending by governments that are in good financial shape, such as Germany — a call that has been mostly ignored by elected officials.

The ECB says it plans to be "fully operational" during the protest, although some employees may work from home.