The latest exchange of fire, sparked by an Iranian attack on a container ship, had already cast further doubt on the peace deal reached last month.

The U.S. and Iran have made conflicting statements about whether the Strait of Hormuz is open to shipping traffic.

The move comes after the U.S. and Iran exchanged fire for the third weekend in a row, raising the specter of a return to all-out war after a shaky ceasefire took effect in June.