Mojtaba Khamenei vows to defend Iran's nuclear and missile capabilities, declaring U.S. defeat and asserting regional dominance.

Ayatollah Mojtaba Khamenei has not been seen or heard in public since he took over for his father, who was killed in the initial round of U.S. strikes in February.

Iran’s supreme leader claimed Thursday that the U.S. has suffered a 'disgraceful defeat' and Tehran will safeguard its nuclear and missile capabilities...