This file photo taken on Nov. 4, 2021 shows Chief Commander of Iran's Islamic Revolution Guards Corps Hossein Salami speaking at a rally in Tehran, Iran. Israeli Defense Minister Israel Katz said on Friday that Israel has launched a "preemptive strike" on Iran. Chief Commander of Iran's Islamic Revolution Guards Corps Hossein Salami and Gholam-Ali Rashid, commander of Iran's Khatam al-Anbiya Central Headquarters, were assassinated as a result of the airstrikes, the official news agency IRNA reported. [Photo/Xinhua]

Israeli Defense Minister Israel Katz said on Friday that Israel has launched a "preemptive strike" on Iran.

Israel Defense Forces (IDF) confirmed in a statement that its jets have completed the first-stage attack, notably strikes on dozens of military targets, including nuclear targets in different areas of Iran.

Chief Commander of Iran's Islamic Revolution Guards Corps Hossein Salami and Gholam-Ali Rashid, commander of Iran's Khatam al-Anbiya Central Headquarters, were assassinated as a result of the airstrikes, the official news agency IRNA reported.

The Israeli airstrikes also killed two Iranian nuclear scientists, identified as Mohammad-Mehdi Tehranchi and Fereydoun Abbasi, the report said.

Israeli Prime Minister Benjamin Netanyahu said in a video address that the goal of the ongoing operation is "to strike Iran's nuclear infrastructure, Iran's ballistic missile factories, and Iran's military capabilities," and will continue "for as many days as it takes."

Explosions were reported in Tehran and counties of Natanz, Khondab and Khorramabad, the Iranian state TV reported, adding that multiple casualties, including women and children, were reported in a residential building in Tehran.

Both Israel and Iran closed their airspace following the attack. Israel has declared a nationwide state of emergency.

In a statement, U.S. Secretary of State Marco Rubio denied any U.S. assistance or involvement in the "unilateral" attack, adding that Israel had told Washington that it believed the strikes were necessary for its self-defense.

Earlier on Thursday, U.S. President Donald Trump warned of a possible "massive conflict" in the Middle East, saying that "I don't want them going in" as direct talks between the United States and Iran are ongoing.

"I want to have an agreement with Iran. We're fairly close to an agreement ... As long as I think there is an agreement, I don't want them going in because that would blow it," he told reporters in the White House.