More than 130 members of the Guardia di Finanza, assisted by Europol and the FBI, swooped on 32 locations to arrest the suspects, mainly Nigerian citizens, and retrieve €2.5 million ($2.7 million), Europol said in a statement.
"Hundreds of individuals and dozens of companies in Europe and beyond have become victims of the sophisticated techniques employed by the criminal group via so-called payment diversion and Internet romance scams," the Hague-based policing agency said.
A payment diversion is when criminals hack a company's communication system and change the account numbers for payments to suppliers and customers.
"Money is therefore inadvertently transferred to bank accounts controlled by the criminal group members who then send the money abroad and ultimately withdraw it as cash," Europol said.
With internet romance scams, victims are targeted by creating fake profiles on legitimate internet dating websites.
The scammers then gain the victims' trust by using false information before trying to convince victims to send money, for instance for a plane ticket.
Police analyzed thousands of financial transactions to reconstruct money flows and destinations.
"The criminal group relied on a network of accomplices who operated a sort of coordinated 'bank run' within a few hours in order to make cash withdrawals from bank accounts chosen as final destinations," Europol said.