“OIG’s Office of Evaluations and Special Projects conducted a review and confirmed that senior embassy staff, including the Ambassador, used personal email accounts to send and receive messages containing official business,” the report, issued on Tuesday, said.
The report appeared as Democratic presidential frontrunner Hillary Clinton faces heavy scrutiny for using a personal email server for official business during her four years as top US diplomat.
It is against US State Department policy for its employees to use private email for official business, the report noted.
“Employees are also expected to use approved, secure methods to transmit Sensitive but Unclassified information when available and practical,” the report read.
In recent months, the State Department released thousands of Clinton’s emails from her private server to the Congressional Committee on Benghazi for their investigation into the role she played before and after the 2012 attack that killed Ambassador Chris Stevens and three US government employees.
The emails revealed the State Department knew Ambassador Stevens’ life was in danger 18 months before the terrorist attacks. Additionally, the emails showed the US government misled the American public about the details of the attacks.