State Department spokesman John Kirby said Tuesday then-Sen. John Kerry used a "non-official" email address to send Hillary Clinton information in 2011 that has since been classified.
The emails between Kerry and Clinton were included among a small batch of records made public by the State Department Friday. It had been upgraded to "secret," the level of classification in government above "confidential," but below "top secret."
"I can tell you the [email] that we talked about being upgraded to secret was sent from a non-official account, and the account from which it was sent is no longer active," Kirby said of the email Tuesday. "I've not spoken to the secretary about his reaction to that being out there."
The State Department's decision late last week to upgrade 22 of Clinton's private emails to "top secret" and block their release renewed speculation that the former secretary of state may be facing deeper legal trouble than experts initially predicted.
More than 1,300 emails have been deemed wholly or partially classified in the eight months since the agency began releasing Clinton's records to the public.
The classified email from Kerry is heavily redacted, but includes the former Democratic senator's thoughts from May 2011 on the visit of the India's prime minister to Kabul.