Vice President JD Vance warned Iran not to "play" the United States as he departed for ceasefire talks in Islamabad, Pakistan.
Despite being a longtime skeptic of foreign military interventions, Vance has been tasked by President Trump to lead negotiations aimed at ending the six-week-old war.
President Trump provided "clear guidelines" for the talks and has previously issued an astonishing threat to wipe out Iran's "whole civilisation" if the conflict escalates.