Two members of a Russian intelligence agency "protected, directed, facilitated, and paid" hackers to break into Yahoo's systems in 2014, compromising 500 million user accounts, the Department of Justice said in an indictment Wednesday.

Two other people, one Russian and one Canadian, were also charged in connection with the hacks, which are believed to be among the largest ever.

The DOJ named Dmitry Dokuchaev and Igor Sushchin as the two members of the Russian intelligence agency, the FSB, suspected of involvement in the hacks.

The Canadian who was charged in connection with the hacks, Karim Baratov, was arrested Tuesday, the DOJ said.

The DOJ said Dokuchaev and Sushchin paid the two other defendants to hack into the Yahoo accounts and obtain personal and financial information from users, including government officials and journalists.