Air defense systems were activated in central Tehran, home to Khamenei's compound and presidential office, reported the Iranian semiofficial Mehr news agency.

Soon after the strikes, Iran launched more than 100 drones toward Israel, Israeli Brig. Gen. Effie Defrin said. The Israel Defense Forces said it was attacking missile launchers and unmanned aerial vehicles launched from Iran, and a military spokesman said on X that strikes were conducted on the nuclear plant in Isfahan in central Iran.

Iran has long denied that it is seeking to develop nuclear weapons.

The United States, which had been publicly urging Israel to hold off on such an attack as the Trump administration continues talks with Tehran on its rapidly advancing nuclear program, said it was not involved in the strikes on Iran and was not assisting with the attacks.

But three U.S. officials told NBC News later Friday that the U.S. is assisting in shooting down Iranian missiles and projectiles targeting Israel. The Pentagon moved a number of military assets into the region in recent days, including Navy destroyers to be positioned off the Israeli coast to help shoot down missiles and other aerial attacks expected after the Israelis launched their initial attack, according to another U.S. official.

President Donald Trump told NBC News in an interview Friday he was pleased with the manner in which the strikes were conducted.

"They had the finest equipment in the world, which is American equipment," he said.

According to a U.S. official, Trump and Netanyahu spoke Friday.

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The International Atomic Energy Agency, the United Nations’ nuclear watchdog, earlier said Iranian authorities had confirmed Natanz, Iran’s largest nuclear site in Isfahan, had been struck but that there was no increase in radiation levels observed there.

Defrin confirmed that Israel struck an underground area of Natanz that targeted critical infrastructure linked to its continued functioning and "inflicted significant damage on this site."

Other targets appeared to be residential compounds for top military officials. A main building for Iran’s Islamic Revolutionary Guard Corps (IRGC), founded in the aftermath of the 1979 Islamic Revolution to defend the regime against internal and external threats, also appeared to have been attacked and could be seen burning on state television.

Among those killed in Israel's strikes was Mohammad Hossein Bagheri, Iran’s most senior military official, multiple Iranian state news outlets reported. Bagheri, who was chief of staff of the Iranian armed forces, had a status equivalent to that of Qassem Suleimani, the commander of Iran’s secretive Quds Force who was assassinated by the U.S. in a drone strike in Baghdad in January 2020.

The Shahid Beheshti University in Tehran said in a statement on Telegram that at least five professors from the school’s community had been killed, including nuclear scientist Mohammad-Mehdi Tehranchi. It said some family members of professors were also killed, but did not share their identities or further details.