Police had to use tear gas and rubber bullets after violence erupted in the Swiss city of Geneva Saturday as a scheduled peaceful protest of a World Trade Organization conference turned violent.

Authorities said that 33 arrests have been made and police were on the streets working to maintain order. An 80-year-old woman in a walker suffered a head bruise when she fell during the tumult of the demonstrations.

Geneva police spokesman Patrick Puhl said that the demonstration started around 2:30 p.m. (local time) and about 3,000 people turned up in the central part of town. This week, World Trade Organization ministers will hold a conference.

Puhl added, “There were three groups who came seeking violence. The troublemakers quickly began attacking banks, hotels and shops, smashing windows and burning four cars, so we had to stop them using tear gas and rubber bullets.”

The general theme for discussion at the conference is “The WTO, the Multilateral Trading System and the Current Global Economic Environment.”

(article and photo source: CNN)