Israel and Iran exchanged fire for the fourth consecutive day on Monday, stocking fears of an all-out war with the potential to drag in others in the oil-rich region and force the US into a more hands-on stance.

The Israeli air force struck storage and missile-launch infrastructure in western Iran on Sunday, Israel’s military said, as attacks in Iran entered a third day.

By Sunday, three days into its campaign, Israel had knocked out centrifuges at Iran’s biggest enrichment facility at Natanz, killed up to 10 of the country’s top nuclear scientists and destroyed key ...