Three suspects alleged to have targeted government and private sector companies in more than 150 countries have been arrested in Lagos, after a joint Interpol and Nigerian police operation.
The year-long investigation, which was code named Operation Falcon, has identified at least 50,000 victims so far.
The suspects are alleged to have used phishing links and mass mailing campaigns in which they impersonated representatives of organisations.
They then used malware programmes to infiltrate the victim organisations before launching scams and syphoning funds.