U.S. Justice Department officials are expected to announce indictments on Wednesday against suspects in at least one of a series of hacking attacks on Yahoo Inc., Reuters reported.

The accused men live in Russia and Canada, Reuters’ source said, with the Canadian far more likely to face arrest. Russia has no extradition treaty with the United States.

It could not immediately be learned whether the group was suspected in the hacking of data about 1 billion Yahoo users or a separate hack of 500 million e-mail accounts. The indictments were first reported by Bloomberg News. Yahoo and the Justice Department declined to comment.

The two largest hacks, and Yahoo’s much-criticized slow response and disclosure, forced a discount of $350 million in what had been a $4.83 billion deal to sell Yahoo’s main assets to Verizon Communications Inc.