PALERMO, Italy (Reuters) - While thousands of migrants reach Sicily each week aboard rescue ships, another sea-borne invasion is under way on the Mediterranean island as hordes of tourists arrive aboard luxury cruise liners.

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Palermo was only the 36th most visited city in Italy in 2015 but Mayor Leoluca Orlando says it is set to be in the top 10 this year, marking a turnaround for the Sicilian capital that was once a Mafia battleground shunned by outsiders.

The United Nations cultural body UNESCO recognized the city’s Norman-Arab heritage in 2015, the growing migrant population is being absorbed into the fabric of society, and next year Palermo will be feted as Italy’s capital of culture.

“Palermo used to be the capital of the Mafia, then the capital of the anti-Mafia, today it is the capital of culture,” Orlando told Reuters in an interview.

Orlando, 70, is seeking re-election at a June 11 ballot and says the tourist surge is a testament to his success in helping Palermo overcome its troubled past and slowly recover from the worst economic downturn in recent history.

The vote pits the veteran Orlando against a revived center-right and the anti-establishment Five Star Movement, making the ballot a barometer of national political sentiment ahead of a general election that is due by next May.

Opinion polls show that while the 5-Star leads the field across Sicily, it will struggle to unseat Orlando, partly because of their own divisions in the port city, but also because of their rival’s tenacity.

Mayor of Palermo for 16 of the last 32 years, Orlando does not belong to any party and refuses to let the center-left groups backing him, including ex-Prime Minister Matteo Renzi’s Democratic Party, use their symbols on ballot papers.

“I was anti-establishment before the Five Star existed. I don’t have any party. My party is called Palermo,” said Orlando, whose reputation was built on his strong anti-Mafia stance in the 1980s and 1990s, when mobsters held sway across the island.

Concerted political and legal action over the past two decades has hammered the organized crime networks. But instead of reaping the benefits, Sicily suffered fresh trauma with the global financial crisis that hit the island like a tsunami.

Palermo’s jobless rate stands at 25 percent and youth unemployment is 70 percent, according to Italy’s CGIL union, double the national average.

Opponents acknowledge that Orlando has restored some of Palermo’s faded splendor, but accuse him of focusing more on tourists than helping impoverished city residents.

More than half a million tourists from cruise ships arrived last year, up from 390,000 in 2010. Arrivals of migrants have also been surging. Some 560,000 have reached Italy over the past 3-1/2 years, with 12,200 drowning in the attempt.

“I think one day there will be another Nuremberg trial over what is going on in the Mediterranean,” Orlando said, referring to the war crimes tribunal at the end of World War Two.

Unlike many Italian mayors, Orlando has warmly embraced the migrant cause, saying Sicily’s long history as an ethnic melting pot explains his openness. “This is not a European city. It is a Middle Eastern city in Europe,” he said.