It was one of the biggest nights in Croatia's sporting calendar: a European Championship soccer qualifying match with Italy. Seconds after kick-off in a game beamed around the world, a gigantic swastika materialized on the pitch under the shocked gaze of European soccer officials.

The swastika, sprayed by an unknown vandal with a chemical that became visible only when floodlights went on to start the game, has become the most potent symbol of a rise in ultra-nationalist sentiment that appears to be bleeding into the mainstream population in the European Union's newest member state.

But it's not the only one. In the mixed ethnic towns of eastern Croatia, road signs in the Serbian Cyrillic alphabet have been destroyed and Serbian Orthodox churches have been vandalized with a "U'' symbol representing the Nazi-linked World War II Ustasha regime. On weekends, Ustasha chants echo at sports venues and rock concerts.

The appearance of such symbols is perhaps unsurprising for a country that during World War II which sent tens of thousands of Serbs, Jews and Gypsies to death camps. But the Balkan state's current leaders have called for change after the global outcry prompted by the swastika on the field.

"This act has inflicted immeasurable damage on the reputation of Croatian citizens and their homeland all over the world," said Croatia's new conservative president, Kolinda Grabar-Kitarovic. "Therefore, we must finally put a stop to such things."

The rise of the right in Croatia has been fueled by deep economic hardship and growing public anger over the inability of the left-leaning government to deal with it, even after the country entered the EU two years ago, fueling dreams of sudden riches that have not materialized.

Minorities, especially Serbs, have complained of fears for their safety since Grabar-Kitarovic was elected president in December. The Anti-Serb graffiti has evoked memories of the bloodshed that engulfed the region during the 1990s Balkans wars that tore apart the former Yugoslavia.

At an event last month in southern Austria, Croatian ultranationalist Ivica Safaric proudly brandished the "U'' Ustasha symbol on a medallion around his neck. His companions in black shirts raised their right arms high in a Nazi salute, shouting out a dreaded battle call "For the homeland — Ready!" used by wartime Croatian fascist troops.

"I respect the Ustasha movement because it created the independent state of Croatia," said Safaric, who fought for Croatia's independence in the 1990s.

The gathering in Bleiburg was a memorial to tens of thousands of pro-Nazi soldiers, their families, children and civilians killed by communist guerrillas at the end of the war in 1945.

Commemorations for the Bleiburg massacre victims are held every year in May, but last month's gathering was by far the largest ever, with an estimated 40,000 people participating. It happened as much of Europe marked the 70th anniversary of liberation from the Nazis, and the pro-Nazi imagery at Bleiburg was met by muted response from Croatia's politicians.

Grabar-Kitarovic endorsed the Bleiburg commemorations and honored the victims just days ahead of the main event, but did not go there when the crowds gathered. She also paid an informal visit to the site of an Ustasha-run death camp in Jasenovac, but did not attend official commemorations of the 70th anniversary of the camp's liberation.

In an illustration of the ideological divide in the country, Croatia's embattled leftist Prime Minister Zoran Milanovic did participate in the official ceremonies at Jasenovac, where at least 80,000 people, mostly Serbs, were killed. He urged Croats to acknowledge what happened in the death camp as part of the Nazi genocidal machine.

Analysts say the right-wing advance in Croatia — traditionally deeply split between left-wing and conservative traditions — has surged to its highest point since the country gained independence from the former Serb-led Yugoslavia in the 1991-95 war.

"Sadly, the extreme right is more visible than ever in the past 25 years in Croatia," said historian Hrvoje Klasic.

Minority Serbs, who fought against Croatia's independence during the Yugoslav wars in the 1990s, have been under increasing pressure by the nationalists. Croatian war veterans campaigning under the slogan "100 percent Croatia" — implying an ethnically pure state — have demanded that Serbs stop using the Cyrillic alphabet in Croatia, although their right to do so is guaranteed by the country's laws.

Alarmed by the surge, thousands of gay activists and their liberal supporters marched in Croatia's capital Zagreb last weekend under the slogan: "Louder and More Courageous: Antifascism Without Compromise."

"We chose the slogan because we don't like where Croatia is heading," said Marko Jurcic, one of the march organizers. "We don't want a 100 percent pure Croatia, we want a diverse Croatia."

Most Croatian officials are downplaying the far-right surge, saying it is part of pre-election campaigning.

"Croatian society is not better or worse than in the other EU countries," said Parliament speaker Josip Leko. "We are in an election year and some themes are being opened by those who want to attract sympathizers."