A U.S. official said that six American warplanes dropped a dozen 30,000-pound bunker-busters on the Fordo nuclear site, and that Navy submarines fired 30 cruise missiles at the Natanz and Isfahan sites. One B-2 bomber also dropped two bunker-busters on Natanz, the official said.

The move, the first time the U.S. has attacked Iran, is a major escalation of the conflict between Israel and Iran.

The world grappled Sunday with the enormous implications after the United States inserted itself into Israel’s war against Iran with an attack that raised urgent questions about what remained of