The State Department has removed emails from its unclassified network from Condoleezza Rice and Colin Powell's tenures.
They're now in secure storage.
The move follows last month's revelation that records of Rice's immediate staff and Powell had a dozen classified messages.
Rice and Powell were President George W. Bush's top U.S. diplomats.
The department's watchdog has been examining email practices of past secretaries of state since last year, when Hillary Clinton's private account and server were revealed.
The department has published Clinton's emails, while classifying over 2,000 of them.
In a letter to the watchdog released Friday, the department said it moved additional emails to a classified system.
It said paper records from Rice and Powell already are stored in a facility authorized to hold secret documents.