Two Russian spies are being indicted by the US Department of Justice over a huge breach of Yahoo user accounts.
Previously, Yahoo had said "state-sponsored" hackers were behind the 2014 incident that affected 500 million accounts.
The firm was criticised for the delay in informing users about the breach.
The stolen data included names, email addresses, telephone numbers, dates of birth and encrypted passwords, but not credit card data, according to Yahoo.
An announcement by the Justice Department detailing the charges is expected to be made later today.
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.