“At most, you could blame four to five people,” Dr. Primorac said, for wearing Ustashe regalia, or giving the Nazi salute during the concert. He emphasized, too, that Croatia was a good friend of Israel and pointed to a photograph on his mantelpiece of himself with the Israeli elder statesman Shimon Peres as evidence.

Image At a recent concert in Zagreb, some fans of the Croatian rock star Marko Perkovic wore the black caps of Croatias World War II Nazi puppet government, known as Ustashe. Credit... Denis Lovrovic

Over the last three years the conservative prime minister, Ivo Sanader, has to some extent managed to shed the country’s image as a nationalist state that once harbored war criminals. The effort has been successful enough that Croatia is a favorite to join the European Union. What was seen for much of 1990s as a war-torn nation is now widely perceived as a prime tourist destination, with 10 million tourists a year and visitors flocking to its Adriatic coast.

Photographs and memorabilia from the Ustashe period are no longer sold openly in Zagreb’s city center. Restaurants no longer display photographs of Ustashe units on their wall. But souvenir shops do still sell key rings and baseball caps with the Ustashe U, as well as the slogan used in Mr. Perkovic’s concerts, “Za Dom: Spremni!” or, “For the Homeland: Ready!”

And many Croats still display an insensitivity to Holocaust issues. Mr. Perkovic’s public affairs manager, Albino Ursic, has a large poster that he designed in 1994 on the wall of his office with the words “final solution.” The poster shows a package of cigarettes marked with a large Swastika and labeled “Adolf Filters,” poking out of a black leather jacket. “It’s an antismoking picture,” he said.

“It won an award in Lisbon,” he added, emphasizing that he viewed himself as left of center. As for Mr. Perkovic’s performance, Mr. Ursic said, the fascist salute is made by soccer hooligans across Europe who have little understanding of it. “It is just teenage rebellion,” he said.

Mr. Perkovic’s patriotic — and sometimes violently nationalistic — songs first became popular here during the Balkan wars, when he fought in the Croatian Army. Most Croats know him better by his stage name, Thompson, given to him during the war, when he carried the submachine gun of the same name. He, too, has recently sought to distance himself from the Ustashe association. In an interview, the soft-spoken singer said he had never raised his own arm to make a fascist salute. Nor, he said, did he encourage people to wear Ustashe uniforms. As for the Ustashe slogan he uses, he claims it is a traditional Croatian salute that predates World War II.