The move came days after the resignation of Daniel P. Driscoll, who had clashed with Defense Secretary Pete Hegseth over the purge of top generals in the Army.
In the first White House press briefing since Karoline Leavitt left as press secretary, the vice president suggested that when the conflict would end was up to Tehran.
Vice President JD Vance took questions from reporters in the White House press briefing room on Thursday, the first briefing held by any administration official there in several weeks.