An unknown person sent texts to and left voicemails for at least five government officials, mimicking the Secretary of State's voice and writing style, The Washington Post reports.

The incident, first reported by The Washington Post, has prompted the State Department to alert all diplomatic and consular posts globally. Officials were advised to warn external partners about potential impersonation attempts.

The State Department says it is investigating the incident, in which an "unknown individual" impersonated Rubio through the app Signal.