A youth camp run by a neo-Nazi group has been broken up by police near Rostock in northern Germany.
Thirty-nine teenagers and children who were attending the camp have been returned to their homes, police said.
The neo-Nazi group that ran the camp had described it as a youth adventure holiday. The police raid uncovered racist propaganda and Nazi material.
The head of Germany's equivalent of the FBI told a newspaper neo-Nazis were adopting increasingly violent tactics.
In an interview with Der Tagesspiegel, Joerg Ziercke said neo-Nazis were "attacking left-wingers and police officers with an aggression that can be seen as a change in strategy".
"Before, neo-Nazis largely avoided violence for tactical reasons but this no longer appears to be the case," the Bundeskriminalamt chief was quoted as saying.
"I see a new character, above all after the riots on 1 May in Hamburg," Mr Ziercke reportedly said.
Clashes erupted in Hamburg when 6,000 people took to the streets to protest against a march involving some 1,500 supporters of the far-right NPD party.
Twenty police officers were hurt and some 60 people were arrested.
Mr Ziercke also told Der Tagesspiegel that arson attacks by right-wing groups were on the rise, with some 15 incidents reported in the first five months of 2008 - five times as many as in the same period last year.