Hillary Clinton Hillary Diane Rodham ClintonJoe Biden looks to expand election battleground into Trump country Biden leads Trump by 12 points among Catholic voters: poll The Hill's Campaign Report: Biden goes on offense MORE’s predecessors at the State Department “routinely” passed along secret information through unsecured email networks, according to an analysis by The Associated Press.

The news agency on Wednesday identified a number of cases in which diplomats’ emails were later classified for containing national security information, yet are available for the public to read through the State Department’s website.

ADVERTISEMENT

Those cases are distinct from Clinton’s use of a personal server to run her own personal email address while in office as secretary of State. But they detail an environment in which it was not uncommon for top diplomats to transmit sensitive information over unsecured networks.

In one message from December of 2006, the AP reported, a diplomat appeared to have pasted into an email the text of a secret cable about China.

The AP found five emails dating to former Secretary of State Condoleezza Rice’s time in office that have been largely censored for containing secrets.

Clinton’s private email server has created an escalating headache for her presidential campaign.

Though the campaign has insisted that she neither sent nor received emails containing information marked classified at the time, intelligence officials have said that a handful of messages contain information that should be secret.

Yet critics have noted that it should have been obvious that some information should have been kept close to the vest. For instance, intelligence officials have said one email containing top-secret information was based on data gathered through spy satellites and the interception of communications.