ZAGREB, Croatia, June 30 — On a hot Sunday evening in June, thousands of fans in a packed stadium here in the Croatian capital gave a Nazi salute as the rock star Marko Perkovic shouted a well-known slogan from World War II.

Denis Lovrovic

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.

Some of the fans were wearing the black caps of Croatia’s infamous Nazi puppet Ustashe government, which was responsible for sending tens of thousands of Serbs, Gypsies and Jews to their deaths in concentration camps.

The exchange with the audience is a routine part of Mr. Perkovic’s act, and the gesture seemed to lack any conscious political overtones. The audience — most of whom appeared to be in their teens and early 20s — just seemed to be having a good time. But Mr. Perkovic’s recent success among a new generation — many of them apparently oblivious to the history of the Holocaust — has prompted concern and condemnation from Jewish groups abroad and minority groups in Croatia

[Despite those objections, the concert — his biggest ever, with an estimated 40,000 fans in the soccer stadium — was shown in prime time on Sunday night on state-owned television, prompting further protests from Jewish and Serbian groups.]

“We don’t want to pay for something that strikes fear into my children, or distances them from their friends or neighbors,” said Milorad Pupovac, leader of the largest Serbian political party in Croatia, referring to the plan for the broadcast.

What has shocked those groups more, though, is that in the ensuing debate, many senior politicians and journalists have said that they see no problem with the imagery or salutes.

“They just don’t seem to get it,” said Efraim Zuroff, the Jerusalem director of the Simon Wiesenthal Center, who has urged President Stipe Mesic to ban future concerts and help outlaw the use of extremist symbols and slogans.

The Croatian government has been trying to improve its image so it can join the European Union, and it did issue a statement after the concert criticizing the open display of Ustashe memorabilia and slogans. But much of Croatia’s political establishment cannot understand what all the fuss is about.

“You can’t see any anti-Semitism here,” Dragan Primorac, Croatia’s education minister, said in an interview. He said he had planned to attend the concert, before rain caused it to be postponed by a day. Others who did get there, though, included a former foreign minister and two Croatian basketball stars.

“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.

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 British-made 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.

Others are unapologetic. Vedran Rudan, a columnist with the Croatian center-right daily Nacional, accused Mr. Zuroff of “extreme arrogance” for writing a letter to the president of Croatia asking the government to bar future Thompson concerts.

She also accused him of branding Croatian youths fascists while ignoring the activities of a well-known ultranationalist member of Parliament, who has close ties with Israel.

“Why do Jews forgive him everything, and the beardless youth and Thompson do not have right to mercy?” Ms. Rudan wrote.

But rights groups here say there is a fundamental problem. While Croatia is now seeking to move away from the nationalist period of the 1990s, the current generation of young people has largely been schooled to believe that the Ustashe government’s actions were no worse than those of Communist leaders in Yugoslavia during the same period.

“They want to put them on an equal footing,” said Danijel Ivin, the president of the Croatian Helsinki Committee for Human Rights. “The education about the recent history of Croatia is not adequate.”

Dr. Primorac said that was slowly beginning to change and pointed out that since 2004, Croatian schools had dedicated a day each year to studying the Holocaust.

Others do not think it is changing quickly enough. “It is an issue,” said Tomislav Jakic, an adviser to President Mesic. “It is far from Ustashe nostalgia that was 15 years ago, when the ghost was first let out of the bottle. But the ghost is still here and it will be for years to come.”