(Bloomberg) -- Illegal betting on sports may approach $1.7 trillion annually and is often used by criminals to launder money, according to a report from the United Nations Office on Drugs and Crime.

The estimate dwarfs the legal sports wagering market, which is about $40 billion, according to the report released Thursday. The increasing number and types of bets are complicating efforts by law enforcement to squash illegal wagering, as is a proliferation of rogue online operators using cryptocurrencies to disguise who is gambling.

Illegal gambling strips sport of its positive, transformative power, the report said, risking its ability to teach and inspire young people.

“In our increasingly globalized world, sport is exposed to complex risks posed by corrupt actors who seek to exploit it for illicit gain,” Ghada Waly, executive director of the office, said in her introduction to the report.

The report concludes that governments, regulators and sports-governing bodies need to work together more to combat illegal wagering, establishing anti-money-laundering units and controls. The fixes should include requirements that operators record customer information and betting data, as well as a ban on anonymous payment processing platforms.

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