More than 300 leftist rioters set fire to train tracks and vandalized streetcars and buses in the western German town of Dortmund on Tuesday, after a May Day demonstration against right-wing extremism got out of control, Dortmund police said Tuesday. The fires were extinguished after an hour, but some tracks and wires were so heavily damaged that train service was disrupted, police said. Four police officers were injured, one seriously. More than 130 protesters were taken into custody, the number of injured demonstrators was not known, a police spokesman said Tuesday night. About 1,800 persons had participated in the protest against right-wing extremists in Dortmund. Later on Tuesday, about 650 members of right-wing groups gathered for a demonstration in a different part of the city, Wieland said. "This was everything else but a peaceful May 1," Wolfgang Wieland said.