Sgt. Benjamin N. Pennington, 26, was killed in Saudi Arabia.
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israel strikes attack targeting military and government sites, officials said.
Iranian state television confirmed that Ayatollah Ali Khamenei was among those killed in Tehran on the first day of strikes. His son Mojtaba Khamenei was chosen on Sunday to succeed him.
Iran is responding to the operation with missile and drone attacks targeting Israel, regional U.S. bases and multiple Gulf nations. Israel is also intensifying its long-running strike campaign against the Iran-backed Hezbollah militia in Lebanon.
------
For updates in Spanish, click here.
President Donald Trump told CNN on Monday that the U.S. military is "knocking the crap" out of Iran and the "big wave" is yet to come.
"We haven't even started hitting them hard. The big wave hasn't even happened. The big one is coming soon," Trump told CNN's Jake Tapper in a phone call.
President Donald Trump is expected to address Iran in remarks at the White House at 11 a.m. ET.
Congressional staff were told by Trump administration officials in private briefings Sunday that Iran was not preparing to launch a preemptive strike against U.S. interests based on U.S. intelligence reports, four people familiar with the briefing told ABC News. CNN was the first to report this news.
This conflicts with what President Donald Trump and senior Trump administration officials said over the weekend.
The administration officials said there were indicators the Iranians could launch a preemptive attack against U.S. forces and allies in the region.
Trump said in his video address to the nation on Saturday, "Our objective is to defend the American people by eliminating imminent threats from the Iranian regime."
Trump told ABC News on Saturday, "I think there was a threat."
"Had we not done 'Midnight Hammer,'" he said, referring to the U.S. strikes on Iran in June 2025, "which was one of the greatest things country has ever done, we would've been faced with a nuclear weapon within a month."
-ABC News' Rachel Scott, Shannon Kingston, Ben Siegel, Luke Barr
The Israel Defense Forces said it's striking Hezbollah targets in Lebanon. A large explosion was heard in Beirut around 9 a.m. ET.
In a statement on X, the U.S. Department of State Consular Affairs urged Americans not to travel to Lebanon.
"If you are in the country, depart Lebanon NOW while commercial flight options remain available," the statement said. "The security situation in Lebanon is volatile and unpredictable."
