Erfurt, Germany  - German police have arrested the principal suspect after a neo-Nazi attack on leftists in a highway rest area, police in the city of Erfurt said Tuesday, but they are still hunting for a Swedish man thought to have taken part in the beating.

Germans were shocked by the February 14 roadside attack, just hours after 10,000 leftists and pacifists had mounted a counter-demonstration in Dresden against a procession by 6,000 far rightists.

Participants on both sides gathered from all over Germany and beyond in Germany.

A 42-year-old man suffered serious head injuries when a busload of neo-Nazis stopped next to two coaches of leftists in a motorway services area and attacked them. Four others were hurt.

Erfurt police said the 32-year-old who had been detained came from the west of Germany and had a record of rightist violence. The man from Sweden and a third man were still being sought. (dpa)