The United States unsealed charges against two Russian spies and two hackers on Wednesday for allegedly pilfering 500 million Yahoo user accounts in 2014.
The indictments represent the first time the US government has criminally charged Russian officials for cyber offences.
The officers of the FSB, Russia’s Federal Security Service, which is a successor to the KGB, were identified as Dmitry Dokuchaev and his superior, Igor Sushchin.
Alexsey Belan, who is on the list of most-wanted cyber criminals, and Karim Baratov, who was born in Kazakhstan but has Canadian citizenship, were also named in the indictment.
The Justice Department said Baratov was arrested in Canada on Tuesday and his case is pending with Canadian authorities.
Belan was arrested in Europe in June 2013 but escaped to Russia before he could be extradited to the United States, according to the Justice Department.
"The criminal conduct at issue, carried out and otherwise facilitated by officers from an FSB unit that serves as the FBI’s point of contact in Moscow on cyber crime matters, is beyond the pale,” said Acting Assistant Attorney General Mary McCord.
McCord said the hacking campaign was waged by the FSB to collect intelligence but that the two hackers used the collected information as an opportunity to "line their pockets."
TRT World spoke to Kate Fisher from Washington DC and Daria Bondarchuk from Moscow on the latest developments.
The United States does not have an extradition treaty with Russia, but McCord said she was hopeful Russian authorities would cooperate in bringing criminals to justice. The United States often charges cyber criminals with the intent of deterring future state-sponsored activity.
The 47-count indictment includes conspiracy, computer fraud and abuse, economic espionage, theft of trade secrets, wire fraud, access device fraud and aggravated identity theft.
Yahoo said when it announced the then-unprecedented breach last September that it believed the attack was state-sponsored, and on Wednesday the company said the indictment "unequivocally shows" that to be the case.
Yahoo in December also announced a breach that occurred in 2013 affecting one billion accounts, though it has not linked that intrusion to the one in 2014.
The breaches were the latest in a series of setbacks for the Internet pioneer, which has fallen on hard times in recent years after being eclipsed by younger, fast-growing rivals including Alphabet Inc's Google and Facebook Inc.
Yahoo’s disclosure of the years-old cyber invasions and its much criticised slow response forced it to accept a discount of $350 million in what had been a $4.83 billion deal to sell its main assets to Verizon Communications Inc.
"We’re committed to keeping our users and our platforms secure and will continue to engage with law enforcement to combat cyber crime," Chris Madsen, Yahoo's assistant general counsel, said in a statement.
TRT World's Kate Fisher has more details from Washington DC.