Maxar Technologies released satellite imagery on Sunday showing activity at Iran's Fordo nuclear facility prior to U.S. air strikes.

The GBU-57 A/B, weighing roughly 30,000 pounds, is a precision-guided bomb capable of penetrating about 200 feet below the surface before exploding.

Iran’s most heavily fortified nuclear site is at Fordo, a hilly area south of Tehran and about 15 miles away from Qum, a city where more than a million people live.