NEW: 🇺🇸 US official says airstrikes will continue for days, not hours.

President Donald Trump announced “major combat operations” against Iran on Saturday, with strikes in the joint U.S.-Israel attack targeting military and government sites, officials said.

The massive operation sparked threats of retaliation by Iran and reports of incoming missiles and drones around the region.

“Our objective is to defend the American people by eliminating imminent threats from the Iranian regime, a vicious group of very hard, terrible people,” Trump said in a video statement.

U.S. officials said the operation could potentially last days, and Trump acknowledged that there may be American casualties.