Hackers using malware have stolen millions from financial institutions in what experts believe what may be one of the biggest bank robberies ever.
In a report from internet security company Kaspersky Lab seen by the New York Times, it is claimed that 100 banks and financial institutions in more than 30 countries have been successfully targeted in the scam.
it is believed that the hackers have stolen at least $300 million, though the report claims that the real amount may be three times as high.
In the report, Kaspersky claims that the hackers use a form of malware which can be downloaded through email attachments, that accesses and monitors the banks' computer systems, allowing the hackers to access confidential information and even operate computers remotely.
It claims that banks in Europe, Japan, and the US were targeted, with most stolen from Russian banks.
It alleges that thieves mimicking bank employees were able to wire up to $10m (£6.49m) at a time into dummy accounts.
Kaspersky says that owing to a non-disclosure agreement, it is prevented from naming the banks targeted.
"This is likely the most sophisticated attack the world has seen to date in terms of the tactics and methods that cybercriminals have used to remain covert," Chris Doggett, the managing director at Kaspersky North America told the newspaper.
No financial institution has admitted being targeted, with the news coming only days after US president Barack Obama urged tech companies and banks to share more information with other financial institutions and government agencies to battle cyber crime.
"Just as we're all connected like never before, we have to work together like never before, both to seize opportunities but also meet the challenges of this information age," Obama told a cybersecurity conference in Silicon Valley, California.