A spokesperson for the paramilitary Revolutionary Guard warned that Iran would change its weapons, military tactics and targets if the conflict with the United States escalates. Meantime, the British military says an “unknown projectile” struck a tanker as it entered the Strait of Hormuz. Two crew members sustained minor injuries in Monday’s attack as the ship headed to port under its own power. The Israeli military remains on alert even as Israel shuts down Monday for the Jewish faith’s holiest day, Yom Kippur. The World Health Organization said 680 people were killed or injured over the course of a week in fighting across Yemen.