(ANSA-AFP) - ERFURT, 04 LUG - Thousands of demonstrators flooded a German city on Saturday, blocking major roads and disrupting public transport, in a bid to shut down the annual congress of the far-right AfD party. About 20,000 people flocked to Erfurt, in Thuringia state, according to police, to protest against the Alternative for Germany (AfD) party that tops national opinion polls. The protesters, led by an alliance dubbed "Resistance", blocked routes into the city, with some abseiling from a motorway bridge. Several groups staged sit-in blockades around the city centre, according to AFP journalists. But most AfD delegates managed to reach the conference centre where the congress began on time. (ANSA-AFP).