Two Russian intelligence agents and two hackers have been charged in a devastating breach at Yahoo that affected at least a half billion user accounts, the Justice Department said Wednesday in bringing the first case of its kind against Russian government officials.

The hack targeted the email accounts of Russian and U.S. officials, Russian journalists, and employees of financial services and other businesses, officials said.

"We will not allow individuals, groups, nation states or a combination of them to compromise the privacy of our citizens, the economic interests of our companies, or the security of our country," said Acting Assistant Attorney General Mary McCord.

One of the defendants, Karim Baratov, has been taken into custody in Canada. Another, Alexey Belan, is on the list of the FBI's most wanted cyber criminals and has been indicted multiple times in the U.S. It's not clear whether he or the other two defendants who remain at large, Dmitry Dokuchaev and Igor Sushchin, will ever step foot in an American courtroom since there's no extradition treaty with Russia. The indictment identifies Dokuchaev and Sushchin as officers of the Russian Federal Security Service, or FSB.