An international hacking ring has stolen as much as $1 billion from more than 100 banks in 30 countries including Russia, the U.S. and China in what could be one of the biggest banking breaches ever. Hackers used phishing schemes and other methods to infiltriate the banks’ systems and lie dormant gathering information about bank operations. Then, they steal funds by transferring money to fake accounts and dispensing cash from ATMs, according to a report that Russian-based Kaspersky Lab is to present Monday at a security conference in Cancun, Mexico. “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,” the lab’s Chris Doggett told The New York Times, which first reported on the incident. In one case, a bank lost $7.3 million through ATM fraud. In another case, a financial institution lost $10 million by the attackers exploiting its online banking platform. Most of the targets have been in Russia, the U.S., Germany, China and Ukraine. More from USA Today by clicking here.