An eighth suspect is thought to have been murdered in April.
The network used fake cards to target banks in the United Arab Emirates and Oman, court documents said.
Prosecutors said law enforcement agencies in Japan, Canada, the UK, Romania and 12 other countries were involved in the investigation.
Arrests had been made in other countries, they said, although details were not released.
"The defendants and their co-conspirators participated in a massive 21st Century bank heist that reached across the internet and stretched around the globe," Loretta Lynch, US Attorney for the Eastern District of New York, said in a statement.
"In the place of guns and masks, this cybercrime organisation used laptops and the internet."
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