Katz said in a statement he had been informed by the military that Iran's security chief Ali Larijani had been killed.
Iranian state media published a handwritten note by Larijani commemorating Iranian sailors killed in a U.S. attack whose funeral was expected on Tuesday but there was no immediate comment by Tehran on Katz's remarks.
Larijani would be the most senior figure assassinated since Supreme Leader Ayatollah Khamenei was killed on the first day of Israeli-U.S. airstrikes on February 28.
Katz said Gholamreza Soleimani, the commander of Iran’s Basij forces, had also been killed.
The Basij militia is a part-time paramilitary force under the control of the Islamic Revolutionary Guard Corps that is often used to quell protests inside Iran.
Israeli Prime Minister Benjamin Netanyahu’s office said in a statement that the Israeli leader had ordered “the elimination of senior officials of the Iranian regime”.
The U.S.-Israeli war on Iran is in its third week, with at least 2,000 people killed and no end in sight. The Strait of Hormuz remains largely closed off and U.S. allies have rebuffed U.S. President Donald Trump's calls for them to help to reopen the vital waterway, through which about 20% of global oil and liquefied natural gas flows.
There was no let-up in attacks by both sides early on Tuesday, with Iran launching missiles on Israel overnight, underscoring that Tehran retains the capacity to carry out long-range strikes despite more than two weeks of pounding by U.S. and Israeli weapons.
The Israeli military said it was targeting "Iranian regime infrastructure" with a new wave of strikes across Tehran, as well as Hezbollah sites in Beirut, a day after saying it had drawn up detailed plans for at least three more weeks of war with Iran.
(Reporting by Reuters bureaux, Writing by Sharon Singleton, Editing by Timothy Heritage)

Iran's Supreme National Security Council Secretary Ali Larijani attends a gathering to mark the death anniversary of former Hezbollah leader Hassan Nasrallah outside his grave in Beirut, Lebanon, 27 September 2025 (reissued 17 March 2026). Larijani has been killed in an Israeli airstrike, according to Israel's defence ministry 17 March 2026. EPA/WAEL HAMZEH