ERFURT: Tens of thousands of demonstrators flooded a German city on Saturday, blocking major roads and disrupting public transport, but failed to halt a congress of the far-right AfD party.

Many Alternative for Germany — AfD — delegates arrived at the conference center in Erfurt in the early hours, before protesters set up their blockades and the event opened on time.

Protesters flocked from across Germany to join largely peaceful demonstrations against the party, which is topping national opinion polls. Police said around 31,000 took part while organizers said at least 50,000.

They blocked multiple routes into the eastern city, in Thuringia state, with some abseiling from a motorway bridge. Several groups staged sit-in blockades around the city center, according to journalists.

City authorities reported numerous disruptions to bus and subway services.