The individual contacted senior U.S. officials and foreign ministers through voicemails and text messages sent via the Signal app.
Authorities suspect the impersonation aimed to manipulate government officials to gain access to sensitive information or accounts.
The State Department is currently investigating the security breach, with the impostor's identity yet to be determined.
This incident occurs amidst broader concerns about the use of encrypted messaging apps for official government communications, following previous security incidents like “Signalgate.”