Around 100 far-right activists were detained Saturday in eight Czech cities as they demonstrated against Roma, officials said. The largest march in northeastern Ostrava drew between 600 and 800 people. Violent clashes broke out between stone-throwing protesters and police, who used teargas to prevent them from entering a district mainly inhabited by Roma. Around 60 of the demonstrators were taken in for questioning, a police spokeswoman told AFP. Smaller marches were held in seven other cities, while human rights activists staged counter-demonstrations in Prague and several other cities. Amnesty International voiced concern early this month over the planned anti-Roma marches, urging the government to \"ensure that these protests do not lead to violence against Roma communities, and that those at risk get the protection they need\". The Czech Republic\'s largely impoverished Roma community numbers between 250,000 and 300,000 people. More than 80 percent of the members surveyed in 2011 said they had experienced discrimination in the past year, according to a poll by the European Union Agency for Fundamental Rights.