Two Russian spies are being indicted by the US Department of Justice over the theft of Yahoo user accounts, according to the Washington Post.
Previously, Yahoo said "state-sponsored" hackers were behind a 2014 breach affecting 500 million accounts.
It was not immediately clear whether the charges, expected to be announced by the Justice Department later today, related to this breach.
Yahoo was criticised for the delay in informing users about the 2014 breach.
The stolen data included names, email addresses, telephone numbers, dates of birth and encrypted passwords, but not credit card data, according to Yahoo.
Last year, users were advised to change their passwords.
Around eight million UK accounts were believed to have been affected - including some users of BT and Sky email services.(BBC)