Sergei Tsurikov, 26, from Tallinn, Estonia, has been arraigned in an Atlanta court on federal charges of conspiracy to commit wire fraud, wire fraud, conspiracy to commit computer fraud, computer fraud, and aggravated identity theft.

According to the Associated Press, he has pleaded not guilty to the charges which, if found guilty could see him jailed for up to 35 years and fined a maximum of $3.5 million.

Tsurikov is accused of being one of the ring leaders of a gang that, in November 2008, hacked into RBS WorldPay's systems and compromised the encryption used by the processor to protect customer data on payroll debit cards.

The ring then allegedly raised the account limits on compromised accounts, and provided a network of "cashers" with 44 counterfeit payroll debit cards, which were used to withdraw more than $9 million from over 2100 ATMs in at least 280 cities worldwide in one 12 hour period.

Authorities say that the cashers were allowed to keep between 30% and 50% of the money they stole, sending the rest back to Tsurikov and other gang members, including Russian Viktor Pleshchuk, using WebMoney accounts and Western Union.

Tsurikov and Pleshchuk are accused of monitoring the "cashout" in real-time from within the RBS WorldPay computer systems before trying to cover their tracks by destroying the data.

Tsurikov, Pleshchuk - who was arrested in Russia in March - Oleg Covelin, 28, from Chisinau, Moldova and a person known only as "Hacker 3" were indicted last November on 16 counts.

United States Attorney Sally Quillian Yates, says: "In November 2008, in just one day, an American credit card processor was hacked in perhaps the most sophisticated and organized computer fraud attack ever conducted. Almost exactly one year later, the leaders of this attack were charged. With cooperation from law enforcement partners around the world, and most particularly in Estonia, we have now extradited to Atlanta one of the leaders of this ring."

Atlanta FBI Special Agent in charge Brian Lamkin, adds: "Complex cyber based criminal investigations such as this are becoming all too prevalent. The advances in technology, while aiding the corporate world and the consumer, also aid the criminal in conducting well coordinated fraud or theft based schemes, often across international borders."