The Department of Justice is set to disclose Wednesday the indictments of at least four people accused of carrying out cyberattacks at Yahoo, DOJ officials told NBC News.

A Wednesday morning news conference will focus on an attack “done with the backing of a nation-state,” the DOJ’s top official on national security told NBC News. Other agency officials say the nation involved is Russia.

Two members of FSB — the Russian intelligence agency — are among those charged, U.S. officials said.

Bloomberg first reported news of the indictments, saying that three of the suspects are believed to be in Russia, and one was in Canada. The Washington Post reported that the indictments would include two Russian spies and two criminal hackers.

Yahoo disclosed two separate data breaches last year, both among the biggest in history. A 2013 attack revealed in December affected more than 1 billion user accounts. In a separate 2014 attack, disclosed in September, information was stolen from at least 500 million user accounts.

Verizon agreed to buy Yahoo before the breaches were publicly disclosed. In February, Verizon cut $350 million from its purchase price for Yahoo. Earlier this month, Yahoo CEO Marissa Mayer said she would forgo her annual bonus in the wake of the incidents.

Yahoo’s top lawyer, Ronald Bell, resigned from the company, after the board of directors concluded that Yahoo’s legal team did not sufficiently pursue information about the hacks.

— Reporting by NBC’s Pete Williams. Written by CNBC’s Anita Balakrishnan.