At least 20 people, including nine policemen, were injured in clashes between police and protesters in Siliana City in northwest Tunisia on Tuesday evening, a security spokesman said. People in Siliana City took to the street to demonstrate against their bad economic and social conditions. The confrontation took place when some protesters in a peaceful march used violence, tried to break into a governmental facility and threw stones at policemen, Spokesman for the Interior Ministry Khaled Tartoush told Tunisian TV. Security forces responded by using tear-gas and clubs to disperse the protesters, he said. He stressed the right of peaceful rallies and protests, but condemned the use of violence as \"totally unacceptable\".