Iran’s warning that Israel faces “punishment” over its suspected killing of senior Iranian commanders in Syria has triggered a clear Israeli response: any operation launched from Iran will be met with action inside Iran. Meanwhile, US President Joe Biden has reiterated his “ironclad” support for Israel as Washington is reportedly pushing Arab states to urge Iran to de-escalate tensions.

The intensifying war of words also comes amid western warnings of an “imminent” attack on Israel—and indications of psychological warfare being stepped up.

Late on Apr. 10, an Iranian news agency cited the country’s defense minister as saying that Tehran’s airspace would be shut down for...