"On Saturday July 5, over half a million people at the (Zagreb) hippodrome will enjoy a spectacle" by Thompson, the Entrio ticket platform said on Facebook.

It said tickets for the event, in the capital of the country of 3.8 million people, were sold out a week after going on sale.

Ustasha symbols are often displayed at Thompson concerts and some fans use the Nazi salute to accompany one of his most popular songs.

But the 58-year-old singer, who became popular during Croatia's war of independence in the 1990s because of his patriotic songs, insists there is "nothing controversial" about the song.

Croatia's pro-Nazi past has become less taboo in the country in recent years and critics accuse authorities of failing to sanction the use of Ustasha symbols.

The Ustasha persecuted and killed hundreds of thousands of Serbs, Jews, anti-fascist Croatians, Roma and others in Croatian concentration camps during World War II.

The Simon Wiesenthal Center, a leading Jewish human rights group, had accused Thompson of glorifying genocide in his lyrics and said the display of Ustasha insignia at his concerts was "neither a coincidence nor a mistake".

Although the Ustasha's so-called Independent State of Croatia was a Nazi puppet, their modern sympathisers see the regime's leaders as the nation's founding fathers.

According to Entrio, July's event at the 47-hectare (116-acre) hippodrome would be the largest-attended paying concert in the world. The Rolling Stones drew 80,000 fans to the same venue in 1988.

In January, Coldplay broke the record for the largest stadium concert of the 21th century with 223,000 spectators over two nights.

The queen of pop Madonna still holds the record with 1.6 million spectators at her free concert at Copacabana Beach, Rio de Janeiro, in 2024.

Thompson is one of the most popular artists in Croatia whose concerts attract tens of thousands. After he took a two-year break for family reasons, 40,000 fans attended his comeback concert last year.

ljv/db