A video posted by President Donald Trump of a massive explosion in Iran’s central city of Isfahan overnight on Monday turned heads, leading to speculation of what target warranted the U.S. to drop a 2,000-pound bunker buster bomb.

Secretary of War Pete Hegseth confirmed the strike during a Tuesday press briefing, pointing to the footage shared by Trump on Truth Social that appears to show multiple secondary explosions likely caused by ignited ammunition or fuel stored at the site.

“The video the president posted last night of Isfahan — an ammo depot struck by U.S. bombers. You see, you don’t get to see many of those videos because, as a reminder, Iran has still shut off the internet to 99.9% of its population,” Hegseth said.

The use of 2,000-pound bunker buster munitions was confirmed by a U.S. official to The Wall Street Journal. While formidable, these weapons are a fraction of the roughly 30,000-pound bunker busters deployed against Iranian nuclear facilities during Operation Midnight Hammer in June, during the 12-Day War.

The strike adds to the list of over 11,000 targets struck so far since Operation Epic Fury began, according to U.S. Central Command.

Isfahan, the third-most populous city in Iran with 2.2 million residents, is a historic city that has, in recent years, become better known for its role in Iran’s nuclear program.

The city is home to the Isfahan Nuclear Technology Center, which was previously targeted by U.S. forces with B-2 bombers carrying bunker busters and nuclear submarines shooting Tomahawk cruise missiles.

Facilities in Isfahan are believed to hold most of Iran’s 400 kilograms of uranium enriched to 60%, which is just below weapons-grade levels. In addition to uranium stockpiles, the city hosts several nuclear facilities, including conversion and manufacturing plants, and research centers.

The ammunition depot strike was not the only reported recent military action in the area.

Earlier this week, Isfahan University of Technology reported it had been struck for the second time since the war began. In a statement carried by the Iranian regime’s Fars News Agency, the university said the attack targeted one of its research institutes.

“According to initial reports, the attack on one of the university’s research institutes also caused damage to several other buildings and resulted in minor injuries to four university staff members,” the statement said.

The university described the strike as part of a broader campaign by “Zionist-American aggressors,” reflecting Iran’s characterization of joint U.S.-Israeli military operations.

CENTCOM did not respond to a request for comment.