Polish police on Monday detained 42 members of gangs involved in drug trafficking and extortion including soccer hooligans ahead of soccer's European Championship starting on June 8 in the capital Warsaw.
Poland, co-hosting Euro 2012 with Ukraine, has seen numerous riots by soccer hooligans in recent years and even shut some stadiums for fans following clashes during the 2011 Polish Cup final.
"Altogether, 42 people were detained, some of them associated with militia groups of pseudo-fans of soccer clubs," police spokesman Mariusz Sokolowski said.
Among those in custody was a leader of hooligan followers of Legia Warsaw nicknamed "Staruch" who became nearly a celebrity in Poland last year as the most vocal and well-recognised adversary of the government's crackdown on hooliganism.
Polish domestic leagues have been marred by racism and anti-Semitism, which prompted former England International Sol Campbell to warn fans not to travel to Euro 2012 games because of violence threat.
Hooliganism in Poland, co-hosting the European Championship for the first time, has been criticised by UEFA officials in the past.
Legia Warsaw were also fined 10,000 euros last year after their fans displayed a banner reading "Jihad Legia" in a match against Israel's Hapoel Tel Aviv..
Prime Minister Donald Tusk, a keen soccer fan, has repeatedly called for peaceful celebration of the tournament he hopes will showcase Poland's successful transformation more than two decades after it overthrew communism in 1989.
"Of course there is a problem, but it's not much bigger than in some other former hosts of the Euros. The government has done a lot to solve the problem of racism and misbehaviour in stadiums in general in recent year," said Poland's Foreign Ministry spokesman Marcin Bosacki.
"As a state with no colonial history we don't have as many minorities as some western European countries. But that does not mean Poles are hostile to them. We invite Mr Campbell to visit, he will not only feel safe but also very much at home."