Protests organized on Saturday by an alliance of activists against the far-right Alternative for Germany (AfD) delayed the start of the party's conference in the eastern German state of Saxony.
The protests come as three of Germany's main political parties are holding rallies on the same day to finalize their election platforms and candidate nominations ahead of the February 23 national elections.
Early polls were called after the collapse of Chancellor Olaf Scholz's three-party coalition in November.
Several demonstrators blocked roads into the center and by 10am (0900 GMT) only a fraction of the roughly 600 delegates had reached the site.
Organizers of the protest said they expected more than 10,000 people to take part in the demonstrations against the AfD.
The president of the AfD party, Alice Weidel, who is to be named as the party's candidate for Chancellor at the two-day conference, was also banned, according to information from AfD sources.
Authorities were prepared for violent protests, with a large police presence, water cannons and a helicopter monitoring the situation.
The police said that there were already isolated attempts to break barriers when the protesters arrived in the morning.
According to a dpa reporter, tear gas was used to disperse protesters who had seized police cars. Demonstrators had damaged the tires of several police vehicles. Pyrotechnics were also thrown at the police during another protest march.
Demonstrators with signs protest against the AfD national party conference. The party conference is to adopt the party's election manifesto and nominate co-chairman Weidel as a candidate for Chancellor. Daniel Wagner/dpa
Police officers remove demonstrators from the street as they try to disrupt the AfD (Alternative for Germany) party conference at the WT Energiesysteme Arena Riesa. The party conference is to adopt the party's election manifesto and nominate co-chairman Weidel as a candidate for Chancellor. Daniel Wagner/dpa
Police officers walk alongside burning pyrotechnics at a demonstration against the AfD (Alternative for Germany) national party conference. The party conference is to adopt the party's parliamentary election program and nominate co-chairman Weidel as a candidate for Chancellor. Jan Woitas/dpa
